Deaf Smith County, on the western edge of the Panhandle, is bounded on the west by New Mexico, on the north by Oldham County, on the east by Randall County, and on the south by Parmer and Castro counties. It was named for Erastus "Deaf" Smith, a famous scout of the Texas Revolution. The county's center point is at 102°30' west longitude and 35°00' north latitude. Deaf Smith County comprises approximately 1,497 square miles of level prairies and rolling plains on the western edge of the Llano Estacado. Its loam soils, ranging from deep chocolate to sandy, support abundant native grasses as well as numerous agricultural products. Elevations range from 3,200 to 4,200 feet above sea level; the minimum average temperature is 22° F in January, and the average annual maximum is 93° in July. The average annual rainfall is 17.37 inches, and the annual growing season averages 185 days. Tierra Blanca Creek flows intermittently across the southern part of the county, and Palo Duro and North Palo Duro creeks run across the northeastern portion of the county. These streams enter the Red River basin in or near Palo Duro Canyon, in Randall County.
The earliest prehistoric inhabitants of these prairies gave way to Plains Apaches, who in turn were forced out by the warlike Comanches and Kiowas. In 1787, and again in 1788, José Mares followed Tierra Blanca Creek in his search for a route from Santa Fe to San Antonio. The Indian wars of the 1870s, culminating in the Red River War of 1874–75, led to the nomadic red man's removal to the Indian Territory. Shortly thereafter ranchers began to appear in the area, and in 1876 the Texas legislature formed Deaf Smith County from the Bexar District. The census counted thirty-eight people in the county in 1880.
By the early 1880s the T Anchor Ranch, headquartered near the site of present Canyon, had spilled over into the eastern part of the county, and the LS Ranch extended over into its northeastern portion. Beginning in 1882, the western half of the county lay within the XIT Ranch, a real estate-cattle project of the Capitol Syndicate. One of the eight XIT division headquarters was established at Las Escarbadas, on Tierra Blanca Creek, in the southwestern corner of Deaf Smith County. The large ranches dominated the county; only a few small stock farms existed among them. By 1890 the county's population had increased to 179, and the census found seventeen farms or ranches in the area, seven of which were smaller than 500 acres. More than 28,600 cattle were counted in the county, while crop production occupied only a few acres: seventy-eight acres was planted in corn and eighty in cotton.
As the cattle industry in the county developed, the rising population created a need for local government. Accordingly, after an election on December 1, 1890, the county was organized with the new town of La Plata as county seat. Jerry R. Dean was elected the first county judge, and the colorful Jim Cook became the first county sheriff. In 1898 the Pecos and Northern Texas Railway, a subsidiary of the Santa Fe line, built tracks from Amarillo to the Texas-New Mexico border at Farwell. This railroad crossed the southeastern corner of Deaf Smith County and brought easy and economical transportation to the local ranchers. The coming of the railroad also brought forth a new town, Hereford, which quickly outstripped the other local hamlets. As a result Hereford became the county seat after an election on November 8, 1898, and La Plata soon faded into oblivion. By 1900 the county had ninety-seven ranches and farms and a population of 843.
Between 1900 and 1910 the large ranchers began to sell their lands, and land-company promotions brought a rush of settlers to the area. With them came significant changes in the local agricultural economy during the first half of the twentieth century. The number of farms and ranches in the county increased steadily during most of this period, rising to 361 in 1910, 382 in 1920, 605 in 1930, and 854 in 1940. The expansion of farming was responsible for most of this growth. In 1900, for example, little if any wheat was grown in the county; by 1920 more than 9,000 acres was planted in that grain, and by 1930 wheat acreage exceeded 26,000 acres. Sorghum became another important crop, and the production of corn also expanded. (see WHEAT CULTURE, SORGHUM CULTURE, CORN CULTURE.) Meanwhile, local farmers diversified into poultry production; in 1929 local chicken farms had more than 51,000 birds, and county farmers sold 208,023 dozen eggs. As the county's economy developed, its population grew to 3,942 in 1910, 3,747 in 1920, 5,979 in 1930, and 6,056 in 1940.
The county's transportation system evolved to meet its growing economic demands. As early as 1920 U.S. Highway 60 (then known as U.S. 366) ran from Canyon via Hereford to Farwell and Clovis. At the same time a roadway was graded from Hereford west to the New Mexico line, thus facilitating movement of crops from most of the county to the rail line; this road was later paved and designated a state farm-to-market road. Beginning in the late 1930s, U.S. 385 (originally State Highway 51) was built from Brownfield to Dalhart via Dimmitt, Hereford, Vega, and Channing. Throughout the 1940s and 1950s a full network of paved farm-to-market roads emerged, linking all parts of the county to either main highways or railroad lines. U.S. 66, which, with the Rock Island Railroad, cuts across the extreme northwestern corner of the county, gave rise to the border community of Glenrio, which declined after the completion of Interstate 40.
After World War II businesses were started in Deaf Smith County to process and ship local products. Vegetable production was introduced on a large scale, and processing and packing plants for onions, potatoes, and other perishable vegetables were also established. In 1964 the Holly Sugar Company opened its $20 million mill and refinery, having contracted with local farmers for the production of sugar beets (see SUGAR PRODUCTION).
Cattle feeding also began to flourish in the 1960s with the opening of several feedlots that used much locally grown grain. By the 1970s these lots were bringing 80 percent of the county's $230 million annual average income. In the late 1980s the county led the state in numbers of cattle fed; it often led the nation in this category. The establishment of feedlots brought commercial production of corn and the establishment of several meat-packing plants in the county. In 1982 Deaf Smith County produced more than 5.75 million bushels of sorghum, 4.75 million bushels of wheat, nearly 4 million bushels of corn, and 251,942 tons of sugar beets. Vegetable production occupied 2,153 acres, planted with carrots, onions, potatoes, and sweet corn.
The population grew steadily from World War II until the 1980s. The number of residents increased from 6,056 in 1940 to 9,111 in 1950, 13,187 in 1960, 18,999 in 1970, and 21,165 in 1980. Economic development brought other changes. The discovery and use of copious underground water in the Ogallala Aquifer in the 1930s led to large-scale irrigation in the 1950s, which further encouraged the expansion of farming. The labor needs of the farming economy drew large numbers of migrant laborers, mostly Hispanic, to the county's packing sheds. As this labor force grew, it became less migratory, and increasing numbers of Mexican Americans moved into the area permanently. By the 1980s, just over 40 percent of the county's population was of Hispanic descent.
Politically, after 1952 Deaf Smith County became more favorably disposed towards the Republican party than formerly, in both state and national elections. Its citizens voted Republican in eight of the nine presidential elections between 1956 and 1988; the county voted for Democrat Texan Lyndon B. Johnson in 1964 in his race against Republican Barry Goldwater.
For several decades the diversified agricultural economy of Deaf Smith County was a thriving, coordinated system. By the early 1980s, however, though farmers produced more on their land, they began realizing a smaller return than at any other time in history. The county population began to drop between 1980 and 1982; by 1992 it was estimated at 19,153, almost 10 percent less than only ten years earlier. Tight economic conditions, combined with a diminishing supply of groundwater, presented new problems. A search for innovations in farming methods intensified. Fearing contamination of the valuable aquifer, residents opposed attempts by the United States Department of Energy during the 1980s to make the county a nuclear-waste dump site.
Communities in Deaf Smith County include Dawn, Glenrio, and Westway. Hereford (population, 15,211) is the county's seat of government and only urban center; in the late 1980s the town had six public elementary schools, two junior highs, a large high school, a county library, and two museums (the Deaf Smith County Historical Museum, and the National Cowgirl Hall of Fame and Western Heritage Center). Every August the town conducts a Miss Hereford contest and hosts the Cowgirl Hall of Fame All-Girl Rodeo. The total population of the county was 19,195, as of 2014.