Wheeler County is on the eastern edge of the Panhandle of Texas, along the Oklahoma border. The center of the county is at 35°25' north latitude and 100°15' west longitude. Wheeler, the county seat, is three miles northwest of the center of the county and 100 miles east of Amarillo. The area was named for Royal T. Wheeler, the second chief justice of the Texas Supreme Court. Wheeler County occupies 914 square miles of rolling prairies and rough river breaks in the area east of the High Plains; elevations range from 2,000 to 2,800 feet above sea level. The red sandy loam and black clay soils produce abundant native grasses as well as wheat, sorghums, cotton, and alfalfa. Cottonwood, black walnut, chinaberry, willow, hackberry, mesquite, and shin oak trees are found along river and creek bottoms and in other watered areas in the county. The North Fork of the Red River and Sweetwater Creek are the two major streams in the county. Numerous lesser streams drain into them, contributing to the rough nature of the terrain. The average annual rainfall is 23.7 inches. Temperatures range from an average minimum of 26° F in January to an average maximum of 97° F in July. The average growing season lasts 208 days. Mineral resources include caliche, gypsum, petroleum, and natural gas.
The area that became Wheeler County was occupied by a Plains Apache culture, which was followed by a modern Apache people, who in turn were displaced by the Kiowas and Comanches around A.D. 1700. The Kiowas and Comanches dominated the Panhandle until they were finally defeated in the Red River War of 1874 and moved to reservations in Indian Territory during 1875 and 1876. Buffalo hunters had begun moving into the area before the Indians were removed. In the spring of 1874 they established a crude outpost, called Hidetown or Sweetwater, on Sweetwater Creek, in the northwestern part of what is now Wheeler County. To curb Indian escapes from Indian Territory, in June 1875 the United States Army established a post near Hidetown. It was named Fort Elliott in 1876 and remained operative until 1890, providing both protection and economic benefits for newly arrived residents. In 1878 the first post office in the Panhandle was established there. As the Indian threat diminished in 1875 and 1876, settlers began to congregate around Fort Elliott and Hidetown, and in 1876 the Texas state legislature established Wheeler County from lands formerly assigned to the Bexar and Young districts. As the buffalo were hunted out of existence, cattle ranching began to develop in the area, and former buffalo hunters, discharged soldiers, and newly arriving ranchers settled into the county. In 1879 the local residents petitioned for county organization. On April 12, 1879, Wheeler County became the first organized county in the Panhandle, with fourteen other unorganized counties attached to it. The small camp of Sweetwater was chosen to be the county seat; the settlement was renamed Mobeetie in 1880, when a post office was established there. Throughout the second half of the 1870s and during the 1880s and 1890s, ranching and Fort Elliott dominated the local economy. In 1890, when the United States agricultural census counted forty-six ranches or farms in the county, almost 9,300 cattle and 1,700 sheep were reported, but only 400 acres were planted in corn, the county's most important crop at that time. In 1900 there were 119 ranches or farms, and 33,000 cattle and 900 sheep were reported, but only 600 acres were planted in corn and ten acres in cotton. For the most part, ranches in Wheeler County at this time were relatively small compared to ranches in other Panhandle counties. Only the J-Buckle Ranch, in the southeastern corner of the county, could be considered large. The United States census found 512 people living in the county in 1880 and 778 in 1890. The population declined after Fort Elliott was closed about 1890, and by 1900 there were 636 people living there.
The ranching industry began to give way to farming around 1900, as a rush for school lands, beginning in 1898 and 1899, led to a substantial increase in cultivation between 1900 and 1910. Railroad construction during this period encouraged immigration and linked the area to national markets. The Santa Fe Railroad, building into the Panhandle in 1887, had missed Mobeetie by twenty miles, but in 1902 the Rock Island built westward across the Panhandle from Oklahoma to Amarillo, and along it several townsites were developed: Crossroads, Lela, Shamrock, Norrick, and Benonine. Sam Pakan, a Slovak from Illinois, arrived in western Wheeler County in 1904. He established the Pakan community and brought in thirteen more Slovak families during the year. By 1910 there were 736 farms and ranches in the county, and over 43,000 acres were planted in corn; another 4,000 acres were planted in cotton that year, 5,000 acres in sorghum, and 2,000 acres in wheat. Meanwhile, ranching remained important to the economy, and 32,000 cattle were reported that year. Wheeler County's population rose rapidly during this period, and by 1910 there were 5,258 people living in the area. The evolution of the economy also contributed to the county's government being moved in 1907 from Mobeetie to Wheeler, which was located closer to the center of the county. Cultivation continued to expand between 1910 and 1930, and cotton became the county's most important crop. The number of farms in the county grew to 994 by 1920, to 1,134 by 1925, and to 1,626 by 1930; meanwhile, cotton cultivation expanded rapidly, especially during the 1920s. Over 12,400 acres were planted in cotton by 1920, and by 1930 more than 93,000 acres were devoted to the fiber. Petroleum discoveries further boosted the economy and population during this period. In 1923 a successful gas well near Shamrock launched a moderate oil boom. The first producing oil well was drilled in 1924, and by the end of the 1920s the entire southwestern part of the county was honeycombed with oil and gas wells, tank batteries, and pipelines. Magic City and Kellerville developed as small oil centers. Oil and gas discoveries also led to more railroad construction. The Santa Fe extended a line from Clinton, Oklahoma, to Pampa in 1929, crossing the northern part of Wheeler County. Townsites on this line included Allison, Zybach, Briscoe, and New Mobeetie (two miles north of Old Mobeetie). The development of the oil and gas industry in the area during the 1920s, combined with the growth of farming, caused Wheeler County's population to more than double during the decade, and by 1930 there were 15,555 people living there. Shamrock emerged as the only successful railroad town, and it soon developed into the county's largest and most successful town, far outstripping Mobeetie and Wheeler.
An unusual boundary adjustment on Wheeler County's eastern border occurred in the late 1920s, when a boundary conflict between Texas and Oklahoma led to a resurvey of the line and a United States Supreme Court decision in 1930. As a result the eastern border of the Texas Panhandle was moved 3,800 feet to the east, to the true 100th meridian. A strip 132 miles long expanded Wheeler and other border counties of Texas at the expense of adjacent counties in Oklahoma. Wheeler County's agricultural progress was reversed during the Great Depression of the 1930s. Low prices, federal crop restrictions, and other factors combined to drive thousands of acres out of production. Cropland harvested declined from 185,000 in 1930 to 167,000 acres in 1949; cotton acreage fell by more than 50 percent during this period, and by 1940 only 42,000 acres were planted in the fiber. Hundreds of farmers were forced off the land: by 1940 only 1,266 farms remained. These losses were mitigated to some extent by railroad construction and by oil and gas production. In 1932 the Fort Worth and Denver Railway extended a line from Childress to Pampa that crossed the southern part of the county by way of Shamrock; and while oil producers did suffer from lower prices during the depression, in 1938 almost 2,743,000 barrels of crude were taken from Wheeler County lands. Nevertheless, as farmers left the area, the county's population declined to 12,411 by 1940. Reduced oilfield activity and the continuing mechanization and consolidation of farms led the population to decline during the 1940s and for most of the second half of the twentieth century. The number of people dropped to 10,317 by 1950, to 7,947 by 1960, and to 6,434 by 1970. The population increased slightly during the 1970s to reach 7,137 by 1980 but then began to decline again. The census counted 5,879 people living in the county in 1990 and 5,284 in 2000. As of 2014, 5,714 people lived in the county. About 68.5 percent were Anglo, 2.9 percent African American, and 26.6 percent Hispanic.
The economic growth of the county after 1900 led to development of a road system to complement the rail network. In 1916 Wheeler County initiated construction of U.S. Highway 66 (now Interstate 40) across the southern part of the county. A road from Shamrock to Wheeler and Mobeetie was also started. Paving of major roads began in 1928 and continued through the 1930s and 1940s. A network of farm-to-market roads was built in the 1940s and 1950s to complement already existing roads and highways. The voters of Wheeler County supported the Democratic candidates in every presidential election between 1880 and 1948, except in 1928. Party loyalties of the county's voters began to shift, however, during the 1952 election, when Republican Dwight D. Eisenhower took the county. The county returned to the Democratic fold in the election of 1956, but Republican candidates won in all the elections held between 1960 and 2004, except in 1964 and 1976. By the 1980s the bulk of the county's population lived in the urban areas and commuted to oil and gas, farming, or ranching jobs. The remainder lived in smaller towns and on isolated farms and ranches in the rural areas. In 1982 about 95 percent of the land was in farms and ranches; 26 percent of the farmland was cultivated, and 7 percent was irrigated. About 73 percent of the county's agricultural receipts was derived from livestock, particularly cattle and hogs. That year the county ranked first in the state for the production of rye, wheat, sorghum, hay, and cotton. Cantaloupes, sweet potatoes, pecans, peaches, and watermelons were also grown. In 2002 the county had 565 farms and ranches covering 533,569 acres, 63 percent of which were devoted to pasture and 35 percent to crops. In that year farmers and ranchers in the area earned $94,022,000; livestock sales accounted for $90,694,000 of the total. Livestock operations, especially fed beef, cow-calf and stocker cattle, swine, and horses, provided most of the county's agricultural income; crops included wheat, grain sorghum, and cotton. In 1982 almost 81,403,000,000 cubic feet of gas-well gas, almost 1,250,000,000 cubic feet of casinghead gas, and 821,000 barrels of crude oil were produced. In 2000 almost 35,638,000,000 cubic feet of gas-well gas and more than 558,000 barrels of oil were produced in the area. By the end of that year 98,332,237 barrels of crude had been taken from Wheeler County lands since 1921. In 2000 there were 5,284 people living in Wheeler County. Wheeler (population, 1,750), the county seat, served as a petroleum center and had large feedlots and a slaughtering plant. Other communities included Shamrock (2,087), Mobeetie (112), Allison (135), and Briscoe (135). Wheeler is home to the Wheeler County Historical Museum. The Pioneer West Museum is in Shamrock, which also holds a St. Patrick's Day Celebration each March.