Gaines County, on the southern High Plains of West Texas, is bordered on the west by New Mexico, on the south by Andrews County, on the east by Dawson County, and on the north by Yoakum and Terry counties. Its center point is at 32°45' north latitude and 102°57' west longitude, about eighty miles southwest of Lubbock. The county was named for James Gaines, a merchant who signed the Texas Declaration of Independence. Gaines County covers 1,489 square miles of rolling land that drains to scattered playas and draws. Sandy loam and sandy soils lie over the county's red-clay subsoil and support a growth of mesquite, shinnery, and catclaw. Cedar Lake (called Laguna Salinas by the Spanish), in northeastern Gaines County, is the largest salt lake on the Texas plains. The county's elevation ranges from 3,000 to 3,600 feet above sea level, and its annual average rainfall is 15.83 inches. The average minimum temperature in January is 16° F; the average maximum in July is 94°. The county has a 210-day growing season. The agricultural components of the local economy earn about $92 million annually from cotton (Gaines County ranks second among cotton-producing counties in Texas), sorghums, vegetables, peanuts, sunflowers, peaches, pecans, cattle, sheep, and hogs. Irrigated land amounts to about 400,000 acres. Gaines County is also one of the state's leading oil counties; it produced 42,810,261 barrels in 1990.
The area was Comanche country until the United States Army campaigns of 1875 and 1876. An Indian burial mound has been excavated near Cedar Lake. It is believed that Quanah Parker, the last great Comanche chief, was born in the vicinity. Cedar Lake was also the site of a skirmish between Indians and United States cavalrymen in October 1875. Buffalo hunters moved into the region in the 1870s, and some of them began ranches and remained in the area after their game had disappeared; the land was plush with grama grasses but limited in surface water. In 1876 the Texas legislature formed Gaines County from Bexar County. Gaines County was attached to Bexar County for administrative purposes in 1876, then to Shackelford County in 1877 and to Martin County in 1885. As early as 1879 ranchman C. C. Slaughter ran herds on much of eastern Gaines County from his headquarters at Rattlesnake Canyon. C. C. Meddin, who moved his family and herd to Gaines County in 1880, was the first permanent settler; the United States census reported only eight people in the county in 1880. In the 1880s and 1890s other ranchers moved into the area, including C. M. Breckon, the Brunson brothers, Bill Anderson, Dave Ernest, Robinson and Winfield Scott of the Hat Ranch, C. Bill Higgins of the Wishbone Ranch, J. E. Millhollon of the MH Ranch, and the several owners of the Triangle H Triangle north of Seminole. Until the early twentieth century cattle raising was the only industry in the county. The population was sixty-eight in 1890 and fifty-five in 1900, when six ranches and 16,432 cattle were reported by the agricultural census.
Farming began to develop in the county after 1904, thanks to the sale of railroad land and the 1895 School Land Act, which gave settlers the right to purchase one section of agricultural land at two dollars an acre and three sections of grassland at one dollar an acre. Although mesquite was not as widespread then as now, farmers had to clear shinnery and mesquite from the land before planting. As more people were moving into the area, the county was formally organized in 1905, with the new town of Seminole designated as the county seat. A courthouse was built in the town in 1906 and a jail in 1907. By 1910, 206 farms and ranches, encompassing 500,772 acres, had been established in Gaines County; about 2,700 acres was planted in corn, the area's most important crop at that time, and farmers had planted more than 2,000 fruit trees (mostly peach). Ranching still dominated the local economy, however: almost 32,250 cattle were counted in Gaines County that year. The expanding population reflected the developing economy; by 1910 the county had 1,255 residents.
Rail transportation was delayed until the Santa Fe reached Seagraves in 1917. Until then, food had to be hauled by wagon seventy miles from Midland, and cattle had to be driven to Midland or Amarillo and shipped from there by rail. In spite of the county's new rail connection, however, an extended drought in 1917 and 1918 drove out some of the earlier settlers; by 1920 only 140 farms remained in the county, and its population had declined to 1,018. Farming took hold during the 1920s, primarily because of a sudden boom in cotton culture in the area. Only 8 acres in Gaines County was planted in cotton in 1910, and only 485 as late as 1920. By 1929, however, 20,566 acres of the county was devoted to the crop. At the same time, sorghum and corn culture also rose significantly, to 56,500 acres by 1929. The number of farms in Gaines County rose quickly during the 1920s, particularly during the first half of the decade: by 1925, 436 farms had been established in the county. Meanwhile, cattle ranching continued at a significant level, though declining in its actual and relative importance to the local economy. In 1929, almost 20,300 cattle were counted in the area.
Many local farmers were devastated during the 1930s as they suffered through the effects of the Dust Bowl and the Great Depression. Many left their farms to look elsewhere for better economic opportunities; between 1929 and 1935 the number of farmers who fully owned their land dropped almost 50 percent, to only eighty-three. The landscape presented a dismal sight, as sand mounds twenty to thirty feet high and thirty to fifty feet wide were formed by winds that drove vegetation against fences and piled up sand drifts on it. Such sand mounds often surrounded fields that had lost their topsoil to expose a surface of unproductive, hard red clay. Cotton production dropped significantly during the 1930s, and by 1940 only 5,580 acres in the county was devoted to growing the crop. Cropland harvested in the county declined from about 56,500 acres in 1929 to 54,732 acres in 1940. Some of the worst effects of the Dust Bowl and the depression, however, were offset by the discovery of oil during the 1930s. Drillers first sought oil in the county in 1912 near Cedar Lake, then tried there again in 1918–19 without success. In 1926 the Humble Oil Company (later Exxon) leased more than 100,000 acres in the western part of the county at fifty cents an acre. Farmers took this lease bounty with wonder and gratitude; leasing continued between 1927 and 1929, and prices rose in some places to ten dollars an acre. Actual oil production was not achieved in the county until 1935. In 1936 drillers found the Seminole Pool at 5,000 to 6,000 feet. Other discoveries followed, and in 1938 more than 650,109 barrels of crude was taken from county wells. Thanks to the oil boom, the population of the county increased significantly during the 1930s to reach 8,136 by 1940.
The 1940s also saw a revival of agriculture sparked by new irrigation techniques. Farmers abandoned the flood method of irrigation because the sandy soil would not hold the water, and began utilizing the vast stores of underground water with sprinkler irrigation. Mechanization also helped turn what had been a desolate area into a blooming garden. Tractors and other machinery displaced the old technique of plowing one row at a time behind a team of horses. By the mid-1970s Gaines County had 1,093 cotton farms, 1,023 feed-grain farms, 162 wheat farms, 121 peanut farms, and other farms that grew peaches, pecans, potatoes, beans, and other crops. As an illustration of the size and breadth of agriculture in the county, the United States agricultural census of 1982 reported production of 2,470,350 bushels of sorghum and 1,488,504 bushels of wheat. The county that year ranked first in the state in cotton production with 186,112 bales, fourth in peanuts with 23,895,785 pounds, and sixth in alfalfa production with 23,642 tons. There were also 32,878 cattle and 645 acres of orchards. Irrigated land amounted to 400,000 acres.
Oil production has continued to play an important role in the county's economy. In 1948 crude production totaled more than 15,663,000 barrels and in 1956, more than 24,395,000 barrels. By the 1970s there were seventeen oilfields scattered over the county, with 1,600 wells producing at from 5,000 to 14,000 feet. Production was almost 60,707,000 barrels in 1978 and about 47,522,000 barrels in 1982. The county produced almost 42,686,000 barrels in 1990. By January 1991, 1,670,602,104 barrels of petroleum had been taken from Gaines County since 1936.
After a half century of voting Democratic, the county gave a majority of its votes to Republican candidates in seven of the eleven presidential races from 1952 to 1992. In the 1992 election county voters supported Republican George H. W. Bush over Democrat William J. Clinton by almost a two-to-one margin. Between 1952 and 1988 county voters supported Republicans in four out of fourteen senatorial races and two of fourteen gubernatorial contests. In the mid-1980s Gaines County had three banks with more than $79 million in assets. The county also had a number of businesses, many associated with the oil industry and agriculture. The population of the county gradually increased after the 1940s, rising to 8,909 in 1950, 12,267 in 1960, 11,593 in 1970, and 13,150 in 1980. In 2014 the county had a population of 19,425, of which 38.7 percent was Hispanic; about 58.3 percent of the population was Anglo, and 2.1 percent was African American. U.S. Highways 180 (west to east) and 385 (north to south) are the major roads. Communities include Seagraves (population, 2,609), Ashmore, Higginbotham, and Loop. Seminole (population, 7,110) is the largest town, market center, and county seat. A settlement of Mennonites has developed near Seminole. The community has its own school and church and maintains its agrarian religious traditions. Most of the Mennonite farmers moved to Texas from Mexico, where regulations against foreign ownership of land had become burdensome.