Matagorda County was created in 1836 (Organized in 1837) and formed as an Original County. Matagorda County was named for the canebrakes that once lined the Gulf of Mexico coastline; Matagorda is Spanish for thick bush. The County Seat is Bay City. The Official County website is located at http://www.co.matagorda.tx.us. See also Extended History for more historical details.
Areas adjacent to Matagorda County are Brazoria County (northeast), Gulf of Mexico (southeast), Calhoun County (southwest), Jackson County (west), Wharton County (northwest)
Researchers often overlook the importance of court records, probate records, and land records as a source of family history information.
PLEASE READ FIRST!!!! Please call the clerk's department to confirm hours, mailing address, fees and other specifics before visiting or requesting information because of sometimes changing contact information.
Matagorda County Clerk has Court Records from 1837, Land Records from 1837 , Probate Records from 1837, Marriage Records from 1837 and Birth/Death Records from 1903 is located at 1700 7th St., Room 202, Bay City, TX 77414-5094; Telephone: (979) 244-7680 .
The County Clerk's Office is the record keeper of the county. The county records include birth certificates, death certificates, marriage licenses, brand registrations, DD214s (military discharges), land / real estate / property records, probate and civil filings.
There are a few online databases for Court, Land and Probate Records which include: Texas Birth Index, 1903-1997, Texas Deaths, 1964-98, Texas Marriage Collection, 1814-1909 & 1966-2002, and Texas Divorce Index, 1968-2002. You may also search the Bureau of Land Management (BLM) which does cover Texas. Many pioneers and settelers bought land from the government instead of individuals.
Below is a list of online resources for Matagorda County Court Records. Email us with websites containing Matagorda County Court Records by clicking the link below:
Birth, marriage, and death records are connected with central life events. They are prime sources for genealogical information.
Texas Department of State Health Services, 1100 W. 49th Street, Austin, TX 78756; (888) 963-7111 or (512) 458-7111; Fax: (512) 458-7711. Please allow up to approximately 6-8 weeks for processing of all type of certificates when ordered through the mail, or 2-5 Days when you order through VitalChek Express Certificate Services. The Vital Records Department has the following records:
ORDERING
There are a few online marriage databases which include: Texas Birth Index, 1903-1997, Texas Deaths, 1964-98, Texas Marriage Collection, 1814-1909 & 1966-2002, and Texas Divorce Index, 1968-2002. Below is a list of online resources for Matagorda County Vital Records. Email us with websites containing Matagorda County Vital Records by clicking the link below:
Few, if any, records reveal as many details about individuals and families as do government census records. Substitute records can be used when the official census is unavailable
Countywide Records: Federal Population Schedules that exist for Matagorda County, Texas are 1850, 1860, 1870, 1880, 1890 (fragment, see below), 1900, 1910, 1920 and 1930.
The Texas State Library holds microfilm editions for all of Texas' federal censuses. Although the 1850, 1860, and part of the 1870 mortality schedules have been published, all the original mortality schedules are at the Texas State Library and on microfilm The 1830 territorial census of Miller County, Arkansas, enumerates an area that is in today's Texas boundaries. The remaining 1890 population schedules which exist for Texas include: Ellis County (Justice Precinct 6, Mountain Peak, and Ovilla Precinct); Hood County (Precinct 5); Rusk County (No. 6 and Justice Precinct No. 7); Trinity County (town of Trinity and Justice Precinct 2); and Kaufman County (Kaufman). Although Greer County in present-day Oklahoma functioned as part of Texas between 1886 and 1896, the 1890 census for this county was enumerated under Oklahoma Territory.
Other Federal Schedules to look at when researching your family tree in Matagorda County, Texas are Industry and Agriculture Schedules availible for the years 1850, 1860, 1870 and 1880. Slave Schedules exist for 1850 & 1860. The Mortality Schedules for the years 1850, 1860, 1870 and 1880. There are free downloadable and printable Census forms to help with your research. These include U.S. Census Extraction Forms and U.K. Census Extraction Forms
Below is a list of online resources for Matagorda County Census Records. Email us with websites containing Matagorda County Census Records by clicking the link below:
Genealogy Atlas has images of old American atlases during the years 1795, 1814, 1822, 1823, 1836, 1838, 1845, 1856, 1866, 1879 and 1897 for Arkansas and other states.
You can view rotating animated maps for Texas showing all the county boundaries for each census year overlayed with past and present maps so you can see the changes in county boundaries. You can view a list of maps for other states at Census Maps
You can view rotating animated maps for Texas showing all the county boundary changes for each year overlayed with past and present maps so you can see the changes in county boundaries. You can view a list of maps for other states and State Department of Transportation Maps at County Maps.
Below is a list of online resources for Matagorda County Maps. Email us with websites containing Matagorda County Maps by clicking the link below:
Military and civil service records provide unique facts and insights into the lives of men and women who have served their country at home and abroad.
The uses and value of military records in genealogical research for ancestors who were veterans are obvious, but military records can also be important to re-searchers whose direct ancestors were not soldiers in any war. The fathers, grandfathers, brothers, and other close relatives of an ancestor may have served in a war, and their service or pension records could contain information that will assist in further identifying the family of primary interest. Due to the amount of genealogical information contained in some military pension files, they should never be overlooked during the research process. Those records not containing specific genealogical information are of historic value and should be included in any overall research design.
Below is a list of online resources for Matagorda County Military Records. Email us with websites containing Matagorda County Military Records by clicking the link below:
Texas tax records constitute one of the most complete sets of available records generated at the county level (by the Commissioners Court) because these documents are maintained by the state. These lists may only include approximately sixty percent of eligible males over the age of twenty-one. Persons exempted from taxes included native Americans, "idiots," "incompetents," and those exempted because of age. This final category of exemptions varied over time. Years without an older age exemption were 1840 and 1862-70. Between 1841-44 exemptions began at forty-five years; in 1845 and from 1850-61 the upward age was set at fifty years. In 1837, 1848, and 1849 the limit was established as fifty-five, and in 1846-7, and 1871 the upward limit was set at sixty years.
Texas Ad Valorem (poll, personal, and real property) tax records for 1836 through 1976 are available in microfilm at the Texas State Library from the date of respective county organization; these are arranged by county and date and are somewhat alphabetized within each division. Microfilm copies are housed in the Genealogy Section. Tax lists for the various counties from creation to 1901 may be borrowed through interlibrary loan. Tax records through 1901-1947 are readily accessible, but not on interlibrary loan. Those for 1948 through 1976 can be obtained upon request.
Below is a list of online resources for Matagorda County Tax Records. Email us with websites containing Matagorda County Tax Records by clicking the link below:
The Repositories in this section are Archives, Libraries, Museums, Genealogical and Historical Societies. Many County Historical and Genealogical Societies publish magazines and/or news letters on a monthly, quarterly, bi-annual or annual basis. Contacting the local societies should not be over looked. State Archives and Societies are usually much larger and better organized with much larger archived materials than their smaller county cousins but they can be more generalized and over look the smaller details that local societies tend to have. Libraries can also be a good place to look for local information. Some libraries have a genealogy section and may have some resources that are not located at archives or societies. Also, take a special look at any museums in the area. They sometimes have photos and items from years gone by as well as information of a genealogical interest. All these places are vitally important to the family genealogist and must not be passed over.
Below is a list of online resources for Matagorda County Genealogical Addresses. Email us with websites containing Matagorda County Genealogical Addresses by clicking the link below:
Obituaries can vary in the amount of information they contain, but many of them are genealogical goldmines, including information such as names, dates, places of birth and death, marriage information, and family relationships.
There are many churches and cemeteries in Matagorda County. Some transcriptions are online. A great site is the Matagorda County Tombstone Transcription Project.
During Texas's colonization period Roman Catholics were the most numerous, but early citizens included those representing other religious faiths such as Baptist, Methodist, Presbyterian, and Christian or Disciples of Christ.
Many cemetery records have been collected and transcribed, including the largest of which is multi-volumes compilation by the DAR and two volumes for Peters Colonists and descendants. The DAR collection, also microfilmed, is available at the Texas State Library and through the FHL.
Some Texas county historical and genealogical societies have published local cemetery and/funeral home records. These are normally available for purchase through the respective society. Two references can help determine which cemeteries have been recorded: Kim Parsons', A Reference to Texas Cemetery Records (Humble, Tex.: by author, 1988), arranged by county; and Sharry Crofford-Gould's, Texas Cemetery Inscriptions: A Source Index
(San Antonio, Tex.: Limited Editions, 1977).
Below is a list of online resources for Matagorda County Cemetery & Church Records. Email us with websites containing Matagorda County Cemetery & Church Records by clicking the link below:
The use of published genealogies, electronic files containing genealogical lineage, and other compiled sources can be of tremendous value to a researcher.
When view family trees online or not, be sure to only take the info at face value and always follow up with your own sources or verify the ones they provide. Below is a list of online resources for Matagorda County Family Trees, web forums and other family type information. Email us with websites containing Matagorda County Family Trees, web forums and other family type information by clicking the link below:
By the time of European exploration in the early 1500s, the central section of the Texas coast, including Matagorda County, was home to several linguistically related subgroups of the hunter-gatherer Karankawa Indians. By the eighteenth and nineteenth centuries the shifting of tribal territories further north forced other tribes, notably the Tonkawa Indians of Central Texas, toward the coast and into Karankawa territory. Alonso Álvarez de Pineda mapped the Texas coastline in 1519, but the first recorded European expedition into the Texas interior was conducted by Álvar Núñez Cabeza de Vaca, who sometime after 1528 probably passed through what later became Matagorda County. Guido de Lavazares landed at Matagorda Bay in 1558, surveyed the northern Gulf Coast, and claimed the area for King Charles V. In 1690 Manuel José de Cárdenas y Magaña mapped Matagorda Bay as part of the Llanos-Cárdenas expedition, and the Alarcón expedition passed through what is now Matagorda County between 1718 and 1719. As early as 1820 plans were made to establish a port at the site of the future town of Matagorda, but none developed, since silt deposited in the bay by the Colorado River made a port impractical at that time. Settlement by Anglo-Americans began in 1822, when the schooner Only Son landed immigrants for Stephen F. Austin's colony at the mouth of the Colorado. Some of the first white residents of what is now Matagorda County were soldiers sent to protect the new settlers from the Karankawa Indians. Austin gave grants in the area to fifty-two families, principally from New York, and in 1827 received permission to settle 300 more within thirty leagues of the coast in areas where settlement had previously been forbidden by the Mexican government. The town of Matagorda, at the mouth of the Colorado River, was founded in 1829 after Austin had convinced the Mexican government that a military post was needed to protect incoming settlers. The town quickly flourished, and settlement proceeded inward from the coast, initially along Caney Creek. A custom house established at Matagorda in 1831 was maintained until the Texas Revolution. Steamers and sailing vessels approached within six miles of the town on Matagorda Bay; other county transportation was also largely by water. The municipality of Matagorda, which comprised the southeast corner of the original Austin grants, was established in 1834 while the area remained under Mexican control.
In events leading up to the Texas Revolution, according to some sources, members of the district of Mina at the Convention of 1832 were actually people from the Matagorda area rather than what became Bastrop County. The District of Matagorda was represented at the Convention of 1833, and Matagordans took an active part in both the councils and subsequent fighting. A local Committee of Public Safety drew up a formal pledge to protect the citizens of Goliad, and troops were sent to aid James W. Fannin. After the war, in 1836, Matagorda County was organized as one of the first twenty-three counties by the Republic of Texas; Matagorda was designated as the county seat. The area's culture reflected the southern backgrounds of many of its inhabitants. Baptist education began at Matagorda around 1829, an Episcopal congregation was established in the area in 1838, and the area's first Methodist congregation was established in 1839. The county's first newspaper, the Tribune, appeared in 1837. A keel boat was reported on the Colorado in 1838, and a ferry known as Cayce's (later called Elliotts) was established in 1849 west of Bay City. As Texas's second major seaport and a port of entry for Texas immigrants from 1840 to 1865, Matagorda rapidly developed transportation and industry. The town had a gristmill in 1859, and the largest sugar mill in the state was built there sometime before 1860. By 1850 there were 2,124 people living in the county, including 913 whites, 1,208 slaves, and 3 free blacks. According to the agricultural census, almost 59,000 acres were in farms in the county that year, including 8,500 acres considered "improved." More than 103,000 bushes of corn, 1,394 thousand-pound hogsheads of sugar, 1,613 bales of cotton, and 60 pounds of rice were produced in the county that year. While cash crops already constituted an important part of the local economy, livestock also played a significant role: almost 32,000 cattle, and more than 2,100 sheep, were also reported in the county that year. The production of cotton rapidly expanded in the county during the 1850s. On the east side of the Colorado, alluvial soils made up of stream deposits provided bottomlands hospitable to plantations, while west of the Colorado the land was used almost exclusively by stockraisers and small farmers. Between 1850 and 1855 a number of slaves were brought into the county, largely by slaveholders from Georgia, South Carolina, and Virginia, to work on large plantations in the bottomlands of the Colorado River and Caney Creek. The region between Matagorda and Brazoria, forty miles away, came to be known as "Old Caney" and was noted for its production of cotton and sugar. Meanwhile, as the profitable plantation economy encouraged planters to bring more black slaves into the area, the county's minority white population took various steps to ensure their control. Citizens established a curfew for slaves and free persons of color as early as 1850, and in 1852 Elder Noah Hill was employed to serve as a missionary to slaves in the county. The need to protect their control over their slaves was also used by white citizens in 1856 to justify expelling the county's entire Mexican population. As one newspaper item contended, the Mexicans in the county were known to "hang around the plantations, taking the likeliest negro girls for wives....they often steal horses, and these girls, too, and endeavor to run them to Mexico. We should rather have anticipated an appeal to Lynch law, than the mild course which has been adopted." By 1858 roughly 30 percent of the improved acreage in the county was used to raise cotton, 6 percent was devoted to sugar, and 20 percent to corn; sea-island cotton was grown on Matagorda Peninsula during this period. In the late 1850s major towns in the county included Matagorda, with 1,200 residents, and Tres Palacios (also known simply as Palacios), which was located west of the Colorado on a high point of land between Matagorda and Tres Palacios bays. By 1860 there were 3,454 people, including 2,107 slaves, living in Matagorda County. Almost 159,000 acres in the county was in farms, and 21,000 acres were reported to be improved. That year the county's plantations and farms produced 8,454 bales of cotton, 507 hogsheads of cane sugar, and 144,000 bushels of corn. John Duncan, one of the county's many wealthy planters, owned real property valued at $150,000 and personal property valued at $128,000, as well as seventy-five slaves and 3,000 cattle. Another planter, James B. Hawkins, had real property valued at $100,000 and personal property valued at $60,750, along with his 101 slaves. While cash crops, especially cotton, had helped to provide this prosperity, cattle remained an important part of the economy in 1860. Almost 38,000 cattle were reported in the county that year, and a cattle company formed in 1849 continued to engage in a lively commerce that had grown between Matagorda Bay, New Orleans, Mobile, and other Gulf points; this trade lasted until the Civil War.
Although the county's voters supported John Bell (the relatively moderate candidate of the Constitutional Union Party) in the presidential election of 1860, the county overwhelmingly supported secession from the union (136 to 8) in a special election held in February 1861. Several Confederate camps, posts, and garrisons were established in the area, and the county shared others with nearby Brazoria County. Capt. E. S. Rugeley's C.S.A. Company was garrisoned at Fort Matagorda, and in 1862 twenty-two soldiers died crossing the bay to skirmish with Union gunboats offshore. In 1863 Confederate soldiers stationed at Matagorda drove cattle off the peninsula, a popular winter pasture, to keep them from being captured by Union troops. DeCrow's Battery was on the southwestern tip of Matagorda Peninsula to guard the east channel to Matagorda Bay. Maj. Gen. John B. Magruder's orders for fortifications at the mouth of Caney Creek to stop invasion by federal forces resulted in 1864 in the construction of an earthen fort called Fort Caney. The fort was made up of four east bank garrisons-forts Ashbel Smith, Hawkins, Rugeley, and Sandcliff-which were later bombarded. Union troops preparing to build a fort in 1864 were repelled by fifty-seven local volunteers. The Confederate gunboat, the John H. Carr, was anchored at Matagorda, along with the Lizzie Lake, a stern wheeler, and a transport called the Luck Guinn. No Union troops entered the county during the war, but the Union's blockade of the Texas coast restricted foreign cotton trade, crippled the commerce of the port at Matagorda, and severely damaged the local economy. Land values and the county's tax base declined after the Civil War and the subsequent emancipation of the slaves. Taxable wealth in the county declined from $2,727,256 (of which $1,095,400 represented the value of slaves) in 1860, to only $1,028,815 by 1866. Farm acreage in the county declined by 30 percent between 1860 and 1870, and the area's cotton-growers, undercut during the war by the Union blockade, never really recovered during this period; in 1870 only 1,590 bales were produced in Matagorda County. There were 3,377 people living in the area that year, a population slightly smaller than before the Civil War began. Almost two-thirds (2,120) of the county's residents were black; twelve Mexicans and three American Indians were also reported in the area that year. Though many of the county's wealthy planters had left the area, others remained and engaged in the cattle trade. The agricultural census reported over 93,000 cattle in the county in 1870, along with about 8,500 sheep. The Stabler Patent Beef Packing Plant, which began canning beef in 1866, and a hide and tallow factory established near the coast before 1870 are evidence of the importance of the county's beef industry during this period.
Though cotton production in the area began to revive after 1870, Matagorda County's economy and population grew slowly until last years of the nineteenth century. From 1875 to 1880 financial difficulties plagued the county government, which was forced to resort to script to finance its activities. There were few towns and little commerce in the area at that time, and the rich farm lands along Caney Creek held the majority of the population; progress awaited the development of improved roads. Steamships of the Morgan Lines maintained a station at Palacios in the 1880s, but the once-thriving port of Matagorda declined, losing its competition with Lavaca and Indianola as a port. About 3,400 acres in the county were planted in cotton in 1880, and 4,307 acres were devoted to the fiber by 1890. Meanwhile, the number of cattle in the area declined significantly: fewer than 20,000 cattle were reported in the county in 1880 and 27,000 in 1890. That year there were 3,985 people living in the county, including 2,524 blacks; post offices had been established at Culver, Elliott, Hardeman, Matagorda, Plader, and Tres Placios. One-fourth of the county's 378 farms were operated by tenants. The county's agricultural economy developed more rapidly during the 1890s, as people from the north-central and central western states moved into the area to take up farming. Bay City was founded in 1894, and because of its location near the center of the county it replaced Matagorda as the county seat. The influx of new immigrants increased land values but discouraged ranching, though the county's herds were improved with Hereford and Durham cattle strains. Cotton acreage in the county almost tripled during the 1890s, and by 1900 12,000 acres in the county were planted in the fiber. That year there were 448 farms and ranches in the county, and the population had increased to 6,097.
Matagorda County's social and political life in the late nineteenth century was marked by racial tension and conflict. The Ku Klux Klan, an organization dedicated to restricting the social and political activities of the newly freed slaves, was active in the area during Reconstruction. Nevertheless at least some area blacks remained active in local politics, and the county consistently supported the Republican tickets in presidential elections between 1872 and 1896. One of the most violent episodes in the county's history occurred in 1887, when the black community known as the Vann Settlement, or the King Vann African Settlement, was attack by armed white vigilantes from Matagorda, Wharton, Brazoria, and Fort Bend counties. According to one local history, the incident convinced the area's black population "that they had best remain in the background and leave the government of the county to the whites." A White Man's Union Association was formed in the county by 1894. Though a majority of the county's voters supported Republican William McKinley in 1896, the number of Republican ballots in the county dropped off dramatically in elections held over the next twenty years. McKinley had won 561 votes in 1896, for example, but Theodore Roosevelt was able to win only ninety Republican ballots in the county in 1904. The area's Democrats had apparently reestablished their control by driving blacks from the political process. In the late nineteenth century the county's economy had been based on corn, cattle, and cotton, but after 1899, when the Matagorda County Rice and Irrigation Company was founded, canal building and the production of rice helped to diversify and invigorate the local economy. Rice plantations grew up along the railroad for fifteen miles above Bay City, which by 1912 was one of the leading rice markets in the state. At first, water dammed up by a raft of debris blocking the mouth of the Colorado River was used to irrigate the rice fields. By 1916 there were eleven irrigation plants, capable of irrigating 286,000 acres in the county, and 235 miles of canals had been built. Farmers turned increasingly to rice production after the boll weevil attacked the central Gulf Coast area in the early 1900s; in 1910, 34 percent of the county's improved acreage was in rice, while less 1 percent was planted in cotton and corn. Sorghum, sudan grass, sugar cane, sweet and Irish potatoes, peanuts, and feed crops were also grown in the area that year, and 27,400 cattle and 46,236 poultry were reported. Though cotton cultivation rebounded in the county during the 1910s, rice acreage continued to expand. By 1920, 38,000 acres in the county were planted in rice, and more than 46,000 acres were planted in cotton. By 1925, 60,000 acres in the county were planted in rice. Much of the agricultural growth of the previous two decades was reversed during the late 1920s, however. In 1930 only 7,452 acres in the county were planted in rice and only 24,000 acres were planted in cotton, a drop of almost 50 percent since 1920. The number of farms and ranches in the county grew to 1,116 by 1910, to 1,616 by 1920, and to 1,673 by 1930. Increasing numbers of the area's farmers did not own their own land, however. Tenants operated 37 percent of the farms in Matagorda County in 1910, 40 percent by 1920, and 60 percent by 1930.
Railroad construction in Matagorda County during the early twentieth century had helped to encourage development by tying the area to national markets and encouraging immigration. From 1900 to 1902 the New York, Texas and Mexican Railway extended its line from Wharton into northeastern Matagorda County, serving Pledger, Podo, Ashwood, Sugar Valley, Grovedale, and Van Vleck on its way to Bay City; it then built west to Cortes, Markham, and Midfield. After Jonathan Edwards Pierce and others donated land, the railroad angled south through Blessing and Pheasant Switch on its way to Palacios on the coast. The railroad later became part of the Southern Pacific. An extension of this line, known as the Hawkinsville Tap, passed from Van Vleck southeast to Rugeley, Cedar Lane, and Gainesmore, reaching Hawkinsville by 1903 and remaining in service until 1932. Meanwhile the Cane Belt Railroad had entered the county from Eagle Lake in 1901, passing through Bay City and stimulating the growth of Wadsworth as it moved south to its terminus at Matagorda on the coast. This line shipped sulphur from Gulf Hill, six miles east of Matagorda, from 1919 until the 1920s, when deposits were depleted and both shipping and the community at Matagorda began to decline. Around 1905 the Saint Louis, Brownsville and Mexico Railway extended its tracks west from Bay City through Buckeye and Blessing and east through Allenhurst and Hasima on its way to Houston. It also constructed a spur from Buckeye to the Tres Palacios Rice and Irrigation Company, to Tres Palacios, and to Collegeport. While the town of Matagorda was the only major town in the county in 1890, by 1913 the railroads had helped to establish or expand many towns and villages, including Bay City, Palacios, Blessing, Collegeport, Markham, Midfield, Wadsworth, Van Vleck, Pledger, and Sargent. Bay City, located at the junction point of all three railroad lines, flourished after 1900. Buckeye was on the St. Louis, Brownsville and Mexico, and Hasima was in the eastern part of the county on the Matagorda-Brazoria line. Gainesmore was on Caney Creek with navigable deep water, and Hawkinsville was in the southeastern part of the county. The economic development of the county was also encouraged by other improvements in the area's transportation network. Around 1902 the Elliott Ferry was replaced by a bridge, and by 1916 the county had 500 miles of roads, half built since 1914. A major improvement in water transportation came with the removal of the massive log jam or raft that extended from the mouth of the Colorado River forty-six miles upstream, trapping sediments and preventing the Colorado from building a delta. Floods on the river occurred in 1913 and 1922, as logs accumulated, alternating with dry years that damaged area rice crops. Efforts to remove the raft had begun as early as 1836, but it was finally blasted to cut a navigation channel in 1929. A large flood that year removed remaining debris.
The discovery of oil and sulphur in the county also helped to diversify the local economy during this period. Oilmen struck gas at Big Hill in 1901, and by 1913 there were producing oilfields at Markham, Clemville, and Big Hill. The Texas Gulf Sulphur Company began mining sulphur in 1919 and founded a company town at Gulf. Meanwhile, manufacturing played only a limited role in the area's economy; in 1920, for example, the twenty-seven manufacturing establishments in Matagorda County employed fewer than 1,000 workers. In 1926 the Texas National Guard established Camp Palacios (later renamed Camp Hulen for its first commanding general) as a summer training site. Between 1900 and 1920 the population of Matagorda County more than doubled, as land speculators helped to attract immigrants to the area. There were 13,589 people living in the area by 1910 and 16,589 by 1920. The area's population continued to grow during the 1920s, and by 1930, 17,678 people lived in the county. Immigration into the area during the early twentieth century fundamentally altered the county's racial composition. More than two-thirds of the county's residents had been black, but by 1930 blacks constituted under 26 percent of the area's residents. A significant increase in the Hispanic population had also occurred by 1930; that year 1,993 residents of Mexican descent were reported in the county.
Cotton cultivation in Matagorda County continued to decline during the Great Depression of the 1930s. By 1940 only 17,000 acres in the area were devoted to the fiber. Rice cultivation in the area revived somewhat, however, so that by 1940, 16,000 areas were planted in that crop. Cropland harvested in the county increased 20 percent during the 1930s, rising from 50,000 acres in 1929 to 62,000 acres in 1940. Meanwhile, the area's petroleum industry continued to grow; Edgar B. Davis, for example, developed oil resources at Buckeye. Almost 1,929,000 barrels of crude were produced in the county in 1938. The county's topography also changed during this period. By 1936 the Colorado River had built a delta across Matagorda Bay to Matagorda Peninsula, cutting the bay into its present eastern and western sections. That same year a channel was dredged through the new delta from the Gulf of Mexico to the town of Matagorda; thereafter, Matagorda was no longer on the coast. In spite of the depression, the county's population continued to grow during the 1930s, and by 1940 there were 20,066 people living in the area. In 1940 a channel was dredged from the Gulf Intracoastal Canal for a deep-water port at Palacios. In 1940 Camp Hulen was taken over by the federal government as an Anti-Aircraft Replacement Training Center; after the beginning of World War II Palacios Army Air Base was established, and part of Matagorda Peninsula became a bombing range. German prisoners of war were housed in the county during the war at installations in Palacios and Bay City; about 400 Germans were interned in the Bay City camp. Some of the prisoners were leased to local rice farmers for field work, while others toiled as cotton choppers, painters, and carpenters. Oil production in the county began to increase significantly during World War II, and as it generally continued to grow for more than twenty years after, the industry became a mainstay of the local economy. Almost 4,563,000 barrels of crude were produced in the county in 1944, more than 6,912,000 barrels in 1948, almost 5,701,000 barrels in 1956, and more than 7,013,000 barrels in 1965. Though oil remained an important component of the local economy during the 1970s and 1980s, production fell off significantly. About 4,780,000 barrels were produced in the county in 1974, 3,323,000 barrels in 1978, and 2,903,000 barrels in 1982; fewer than 1,605,000 barrels were produced in the county in 1990.
Partly because of farm consolidations and mechanization the number of farms in the county steadily declined in the decades after World War II, dropping to 1,329 by 1960, to 902 by 1970, and to 703 by 1980. Nevertheless the area's population grew during this period, rising to 21,559 by 1950, to 25,744 by 1960, to 27,913 by 1970, and to 37,828 by 1980. Much of this growth can be attributed to the area's petroleum resources and to new industries, which began to move to the area in the 1960s. In 1956 the Colorado River Industrial Development Association was organized to encourage economic development of counties along the Colorado. In the 1960s a Celanese Corporation plant was established at Bay City for access to raw materials and the Intracoastal Waterway. Plants owned by Conoco and E. I. DePont de Nemours Company (Occidental Chemical after 1987) followed, along with a Marathon Oil Company gasoline refinery and several plants producing natural gas and other gases. Meanwhile, the area's agricultural sector remained important to the local economy. By the 1970s the county was a leading cattle-producing area, and significant amounts of cotton, grain sorghums, soy beans, and corn were grown there; the area was the third largest rice producer in the state after Wharton and Jefferson counties. The demographic profile of the community continued to evolve. By 1982 the population was 20 percent Hispanic, 14 percent black, 20 percent of English descent, and 16 percent of German or Irish descent. Many people still engaged in farming, but 10 percent were employed in the construction industry, and more than half the population resided in either Bay City or Palacios. A total of 782 businesses operated in the county in 1982, and 12 percent of the labor force was employed in manufacturing. The fishing industry and fine recreational facilities for hunting also helped to diversify the economy. Meanwhile, most of the area's railroad trackage was no longer used. Though most of the spurs had been abandoned by the 1980s, the Missouri-Pacific's main customer was the Celanese Corporation in southwest Bay City. The Palacios branch of the Texas and New Orleans Railroad was last used in the 1970s when it shipped supplies for the construction of South Texas Nuclear Project, a twin-reactor plant managed by Houston Lighting and Power Company. The STNP began operations at Bay City in 1988 and supplied electricity to Houston, San Antonio, Austin, and Corpus Christi. In the early 1990s the fear of leaks in the nuclear plant led to its closure for several months. In the 1990s the Houston-Galveston Area Council provided regional planning to guide unified development in the county and nearby areas.
In 1990 there were 36,928 people living in Matagorda County, slightly fewer than in 1980. That year almost half of the county's residents lived in Bay City (1990 population: 18,170), the county seat and a center of petrochemical production in the area. Other communities included Palacios (4,148), Markham (1,206), and Van Vleck (1,534).