McMullen County is in southern Texas surrounded by Atascosa, Live Oak, Duval, and La Salle counties. Tilden, the county's largest town and the county seat, is in the north central part of the county at the intersection of State highways 72 and 16. The center of the county lies at 28°20' north latitude and 98°32' west longitude. McMullen County was named for John McMullen, the Irish empresario. The county comprises 1,159 square miles of usually flat to rolling terrain covered with mesquite, scrub brush, cacti, chaparral, and grasses. Elevation ranges from approximately 150 to 450 feet. Soils in the county vary: in some areas light to dark loamy soils cover reddish, clayey subsoils, with limestone within forty inches of the surface; in others cracking, grey to black clayey soils predominate. Most of the county is drained by the Nueces River, which flows northeasterly from the southwestern corner of the county and bisects its eastern border. The northern half of McMullen County is drained by the Frio River, which empties into the Choke Canyon Reservoir in the northeastern corner of the county. In 1982, 87 percent of the county's land was devoted to ranching and farming and 2 percent was cultivated. Livestock and livestock products accounted for 93 percent of its agricultural income. Mineral resources include uranium, salt domes, sand and gravel, oil, natural gas, and lignite coal. Crude oil production in 1982 totalled 899,661 barrels; 20,209,632,000 cubic feet of gas well gas, 693,355,000 cubic feet of casinghead gas, and 56,627 barrels of condensate were also produced. Temperatures in McMullen County range from an average high of 98° F in July to an average low of 42° in January; the average annual temperature is 71° F. Rainfall averages 24 inches per year, and the growing season lasts for 290 days.
Prior to settlement in the nineteenth century the landscape of the area was different in appearance than it is today. Grasslands punctuated by clumps of mesquite and oak trees supported several varieties of wildlife, including deer, turkeys, coyotes, wild horses, and panthers. In a few areas, small springs and seeps fed pools and waterholes that harbored beavers, alligators, fish, crawfish, and mussels. The springs and seeps also helped to keep streams like San Miguel Creek flowing all year round, and thus helped to perpetuate occasional stands of large oaks. Artifacts dating from the Paleo-Indian period (9200 B.C. to 6000 B.C) demonstrate that humans have lived in the area of McMullen County for perhaps 11,000 years. The local Indian population seems to have increased during the Archaic period (6000 B.C. to A.D. 1000), when many groups of hunter-gatherers spent part or all of their time in the area. During this period the inhabitants subsisted mostly on game, wild fruits, seeds, and roots. Tools were carved from wood and stone by these early inhabitants, who also wove baskets and rabbitskin clothing. The hunting and gathering way of life persisted into the Late Prehistoric period (A.D. 1000 to the arrival of the Spanish), though during this time Indians in the area learned to make pottery and hunted with bows and arrows. Many of the native inhabitants of South Texas traveled to the area that is now McMullen County to eat and gather prickly pear during the tuna season. By 1725 the Coahuiltecan Indians, native to the area of McMullen County, were squeezed out by Lipan Apaches and other Indian tribes, who were migrating into the area, and by the Spanish, who were moving up from the south. Some of the Coahuiltecans from the area that is now McMullen County might have been taken by the Spanish to missions at San Juan Bautista in Coahuila.
Though no permanent Spanish settlements seem to have been established in the area now known as McMullen County, Spaniards traveled across it at various times. Alonso De León, for example, passed through the area in 1689 and 1690, as did Diego Ortiz Parrilla in 1766. Since the old Presidio Road (Camino Real) passed to the north and west of the area, and the San Antonio-Laredo road cut only through its northwest corner, there was relatively little Spanish experience or interest in the area. After the Mexican War of Independence the Mexican government used colonization contracts and land grants to promote the settlement of Texas. In 1825 the Mexican state of Coahuila granted a colonization contract to Benjamin Drake Lovell and John G. Purnell for a tract of land that included all of present-day McMullen County north of the Nueces River. In 1828, after Lovell and Purnell had failed to fulfill the terms of their contract, the same land was assigned to John McMullen and James McGloin, who contracted to settle the area with 200 Catholic immigrants. By 1835 the Mexican government had issued perhaps fifteen grants of land in the area of present McMullen County to colonists associated with the McMullen-McGloin project. None of these grantees actually settled on the land assigned to them, however. By 1836, when Texas seceded from Mexico, the area remained populated almost entirely by the Indian bands that roamed through the area.
Between the Texas Revolution and the Mexican War of 1846–48, most of what is now McMullen County lay in the disputed area between the Rio Grande and the Nueces River. Asserting its claim to the area, the Republic of Texas issued forty-five land grants to property in the area between 1841 and 1845, including a large grant to an English company. It is doubtful that any of these grantees permanently occupied their land, however. Neither the Republic of Texas nor the Mexican government could establish control over this strip of contested land, and it became a haven for outlaws and desperate characters. When William Bollaert, an English land speculator, traveled through the area between the Nueces and Frio rivers in 1844, for example, the only people he encountered were convicts who had escaped from a prison in Laredo. Even after the Treaty of Guadalupe Hidalgo definitively assigned the Nueces Strip to Texas, outlaws and unfriendly Indians delayed development of the area for years. When McMullen County was officially established from parts of Bexar, Atascosa, and Live Oak counties in 1858, the area had only begun to be settled. In the years just prior to the Civil War settlers began to move into northern McMullen County, particularly along the Frio River; the area's grasslands and many wild cattle and mustangs offered economic opportunity for those willing to risk attack. In 1858 a group of about thirty people established a settlement where Leoncita Creek met the Frio. By fall of that year they had built eight to ten crude dwellings and soon afterward began to cut a road to meet the San Antonio-Laredo road that lay to the west. Dubbed Rio Frio, later Dog Town, and then Tilden, this was the first permanent settlement in the county. About ten miles to the east of the Rio Frio settlement, along a broad curve in the Frio River, another group established what came to be known as Yarbrough Bend, a loose community composed mainly of squatters. By 1860 there were perhaps 100 settlers in the county. In the early years of settlement, residents lived on a subsistence level, raising small patches of crops and killing wild game. They also relied to a great extent on the wild cattle and horses that grazed in the area. Until about 1867 the settlers often found that there was a better market for mustangs than for wild cattle, but they also engaged in "cow hunts" to build herds and for sale along the Texas coast and, later, in Kansas. By the late 1860s and early 1870s a number of ranches had been established, mostly in the northern part of the county. For protection, ranchers often grouped their dwellings together. By 1870 Yarbrough Bend, for example, included perhaps thirty families; others clustered along San Miguel Creek or at the Rio Frio settlement, which had come to be called Dog Town.
During the early 1860s the settlement had grown slowly. In 1862 Levi J. Edwards built the town's first general store, and shortly after he added a saloon. About that time, too, the town built its first school. The settlement also acted as a home guard post for the Twenty-ninth Brigade of the Texas Confederate militia during the Civil War. After the war ended Dog Town grew fairly rapidly. By 1870 there were about 190 people living in the town, and by 1876 it included four general stores, one grocery store, two saloons, a drug store, and a hotel. In 1877, when McMullen County was officially organized, Dog Town was chosen as the county seat. That same year, the town was formally surveyed, and its name was changed to Tilden. By 1880 stagecoaches on the San Antonio-Laredo road began making regular stops at Tilden, and in 1881 McMullen College, a small academy, opened. By 1884 Tilden was described as a "post village" with about 250 residents, but it included the college, Methodist and Catholic churches, two druggists, a blacksmith, a cabinetmaker, and the Tilden Ledger, a weekly newspaper. By 1890 the town had grown to 600 residents. The growth of Tilden in some ways indicated the development of the county as a whole in the late nineteenth century. Cattle ranchers established themselves in the county during this period, especially during the 1880s, when barbed wire fencing was introduced. During the 1870s a number of ranchers had begun to accumulate large herds and landholdings; some of the smaller ranchers were squeezed out. By the 1890s the era of the free range was over; most of the squatters in the Yarbrough Bend area, for example, had either moved, acquired ranches, or had been pushed off the land. Only seven farms or ranches existed in McMullen County in 1870 and only twenty-nine in 1880. By 1890 the county had seventy-seven farms or ranches, and of these only seven were smaller than 100 acres in size; forty-two had 1,000 acres or more. The county's population steadily increased during this period, rising from 230 in 1870 to 701 in 1880 and to 1,038 by 1890.
Sheep ranching was also an important part of McMullen County's economy for a time. Small flocks of Merino sheep were brought into the region during the early 1860s, and as the demand for wool increased during the 1870s sheep actually came to outnumber cattle. In 1870 5,030 sheep were counted in the county; by 1880 41,047 were reported, and by 1882 there were about 80,000 sheep. Ranchers sold the wool in San Antonio, and sometimes herded sheep to buyers in Galveston and Indianola. For a number of reasons, including a sharp drop in wool prices, a severe drought, and the depletion of grasslands, however, sheep raising quickly declined in McMullen County, as it did in most parts of South Texas during the late nineteenth century. By 1887 there were only 37,000 sheep in the county, and by 1900 the number had dropped to only 1,036. Nevertheless the sheep industry helped to shape the social composition of McMullen County. Almost all of the early residents of the county had been Anglo-Saxon Protestants. With the development of sheep ranching on a large scale, however, many people of Mexican descent moved into the county, often to work as shearers or shepherds. By 1880 101 people born in Mexico lived in the county, or almost 15 percent of the total population. None of these owned any land, sheep, or horses, however; though some Anglos worked as shepherds, too, the rise of sheep ranching had, in effect, added a new ethnic dimension to the county's social and economic life.
At the turn of the century ranching completely dominated McMullen County's economy and set the tone for its culture. No manufacturing establishments were reported there in 1900, but ninety-one farms and ranches that year covered 505,000 acres. Little land was devoted to crops; only 2,859 acres were reportedly "improved." The county's real wealth lay in 25,000 cattle, 13,000 horses, 10,779 mules, and 1,044 hogs and swine. Most of the its 1,024 residents lived on scattered ranches concentrated in the northern and central sections of the county. Tilden and Nopal, a village six miles north of Tilden, were the only towns, and they remained relatively small and undeveloped. The county's economic profile began to change in the first two decades of the twentieth century, as the oil and gas industry grew in importance. Trace amounts of oil, sulfur, and natural gas found in water wells as early as the 1890s had encouraged wildcatters to search for petroleum deposits in the area, and by 1905 oil explorations were conducted in a number of locations along the Frio River. In 1908 a water well being drilled on the Charles Byrne Ranch east of Tilden erupted in a geyser of gas and water 100 feet high. After Byrne's son discovered an oil seep on the Frio River in 1915, the family reported their findings to William M. Stephenson, an oil entrepreneur. Soon Stephenson's company, the Grubstake Investment Company, had leased 300,000 acres of land in the county. Stephenson's company had its first major success in November 1917, when a drilling crew found natural gas at a depth of 816 feet on a site near present-day Calliham. The well produced 62,000,000 cubic feet of gas per day; by 1923 Stephenson's company had laid gas lines and was piping gas to San Antonio. Meanwhile, in 1922, the company also made the first major oil strike in the county on a ranch owned by Joseph T. Calliham. So many people had moved to the prospecting area by that time that Stephenson arranged to lay out a formal townsite on the ranch. In 1923 the new town-called Calliham, after the owner of the site- was granted a post office, and a boom town rose quickly on the spot. During its heyday in the 1920s Calliham had three two-story hotels, four cafes, a dance pavilion, a newspaper printing office, and a number of other businesses.
Between 1900 and 1920 the county also saw several attempts to imitate the ambitious land development projects taking place in other South Texas counties at the time. About 1902, for example, the Boston and Texas Corporation began to develop the town of Crowther fourteen miles northeast of Tilden. Hoping to make a new agricultural center of their 1,600-acre townsite, the developers cleared surrounding land and built a reservoir and other irrigation projects. The Crowther development was advertised in northeastern states such as Massachusetts, New York, and Pennsylvania, and for a time seemed to be taking hold: a number of New Englanders purchased land at the site, and by 1910 the town had 300 residents. At least six similar projects were planned or attempted in the county during the early twentieth century, though none was quite so ambitious as the Crowther development. Zella, on the northwestern edge of the county, was established in 1913; Wentz, ten miles southeast of Tilden, was laid out in 1914; and Norwell, in the northeastern part of the county, was begun in 1914. By the early 1920s, however, the boomlet had collapsed. Three planned towns-San Fernando, Brazil, and McMullen-never materialized, and Norwell and Zella failed to grow beyond modest beginnings. Crowther and Wentz experienced sudden and permanent declines after 1920. There were several reasons for these failures. Limited rainfall in 1916–17 became a devastating drought. Unlike their counterparts in the Winter Garden counties to the west, most of the prospective farmers who came to McMullen County during this period found no reservoirs of underground water suitable for large-scale irrigation projects. And the reluctance of railroad companies to extend their tracks into the county made agricultural development all the more difficult. Tilden, the county's first and largest town, lost population between 1900 and 1930. The population of the county as a whole fluctuated from 1,091 in 1910, to 952 in 1920, and to 1,351 in 1930.
Nevertheless, crop farming did become a significant part of the county's economy during this period. A number of irrigation experiments had been conducted by 1904, though with unknown results. By 1909 4,400 acres of land was under cultivation; by 1920, after more land in the northeastern and eastern sections of the county was put to the plow, 5,000 acres were classified as "improved." Cotton, corn, and sorghum were most often planted. The number of farms increased from ninety-one in 1900 to 130 in 1920; the value of farmland jumped from $800,000 to more than $6,000,000 during the same period. Dry weather, high farmer indebtedness, and a drop in farm prices led to a severe shakeout during the early 1920s. Many farmers were forced to sell their land, and by 1925 almost one of every four farms had disappeared; only 105 remained. Thanks largely to a dramatic increase in cotton cultivation, however, farming increased during the late 1920s. By 1930 over 8,500 acres were devoted to cotton alone, while the number of farms increased to 202; in all, 12,000 acres were harvested in McMullen County that year. The years of the Great Depression were difficult for the residents of McMullen County. An extended drought, low commodity prices, and a tick-fever quarantine devastated the county's agricultural base; by 1939 only 162 farms remained. It has been estimated that 2,000 people lived in McMullen County in 1928, but by 1930 only 1,374 residents were counted, and in 1940 the population was 1,351. With the eradication of tick fever during the mid-1930s, the end of the drought in 1939, and an improvement in commodity prices during World War II, the county's ranchers recovered. New earthen tanks were built to conserve water, and other improvements such as cross-fencing and new breeds of cattle were introduced. After World War II the cattle industry continued to prosper. While a few farmers grew crops such as grain sorghums and corn, largely in the northeastern part of the county, cattle ranching continued to be the primary economic activity. In 1986 cattle ranching produced an estimated 90 percent of the county's income.
From the Great Depression and World War II to the 1990s the population of McMullen County dropped slowly but steadily. At the same time, virtually all of the small towns established before the depression disappeared or shrank. In 1940 1,374 people lived in McMullen County; in 1950, however, the census counted only 1,187 people, and by 1970 the number had dropped to 1,095. Meanwhile, oil production became an important part of the economy. In 1930 only 10,000 barrels of oil were extracted from county lands, but as early as 1934 production jumped to 225,000 barrels. By 1940 748,000 barrels were pumped. After a brief decline in the early 1940s production began to rise again. In 1946, 287 wells produced 514,000 barrels of oil in McMullen County. In 1956 882,000 barrels were pumped, and in 1968, 1,335,000 barrels were extracted. Though production declined during the late 1970s and early 1980s, after 1986 more oil was being pumped than ever. In 1989 production was 5,701,325 barrels; by the end of that year 77,000,000 barrels of oil had been pumped in McMullen County since the first well was drilled.
The voters of McMullen County favored the Democratic ticket in every national election from 1884 to 1920. Since then, however, election returns have usually reflected national election results. During the 1920s, as the nation as a whole voted for Republicans, McMullen County voters favored Republican candidates Calvin Coolidge and Herbert Hoover; from 1932 to 1944 voters favored Democrat Franklin Roosevelt and in 1948 Harry Truman. Then, in 1952 and 1956 the vote went to Republican Dwight D. Eisenhower. In fact, county voters predicted the winners of all but three presidential elections between 1920 and 1992. The only exceptions occurred in 1960, when voters narrowly chose Richard Nixon over John Kennedy, 241 to 240; in 1976, when they picked Gerald Ford over Jimmy Carter, and in 1992, when they supported George Bush over Bill Clinton. In 2014 McMullen County had a population of 805; abouth 60.5 percent were Anglo, 1 percent African American, and 36.6 percent Hispanic. Most of the towns that had appeared during the early twentieth century had severely declined or had disappeared altogether, and people were increasingly concentrated in Tilden. Reflecting this trend, school districts had regularly consolidated. In 1930 the county had seven school districts; by the early 1980s there was only one school district, with one elementary school and one high school. Tilden, with an estimated population of 321 in 2014, continued to be the principal town and county seat; its chief economic activities included kitty-litter production, tourism, and the processing of natural gas.