Crosby County is on the eastern edge of the southern High Plains, bounded on the west by Lubbock County, on the north by Floyd County, on the east by Dickens County, and on the south by Garza County. It was named for Stephen Crosby, a Texas land commissioner during the mid-nineteenth century. U.S. Highway 82 runs west to east across the county, and State highways 207 and 651 are major north-to-south roads. The center of the county lies at 33°37' north latitude and 101°18' west longitude, about thirty miles east of Lubbock. Most of the western half of Crosby County, flat land covered by rich loam, lies above the Caprock, and the eastern part of the county and its southwestern corner are broken country below the Caprock. Drainage is to the forks of the Brazos River, White River, and numerous playas. Blanco Canyon crosses the county from northwest to southeast; at Mount Blanco the canyon is about 250 feet deep and 1½ miles wide, and is traversed by the White River. The county covers 911 square miles; its altitude ranges from 2,100 to 3,200 feet, and the average annual rainfall is 21.01 inches. Vegetation includes mesquite, hackberry, cottonwood, cedar, catclaw, cacti, and grasses, particularly curly mesquite, grama, salt, and sage. The average minimum temperature in January is 26° F; the average maximum in July is 94°. A growing season of 206 days yields $45 million average annual income from cotton, sorghums, wheat, corn, soybeans, sunflowers, cattle, hogs, and poultry. Irrigated land totals 125,000 acres.
Artifacts dating back 13,000 years to the early Paleolithic era have been discovered in Crosby County. Flint-pointed darts used with the atlatl (a type of spear-thrower) have been found and identified as Clovis, Eden, Agate Basin, Angostura, Folsom, Plainview, Meserve, Scottsbluff, and Sandia points. The darts were used to hunt the mammoth, mastodon, saber-toothed tiger, and giant ground sloth, all of which disappeared some 8,000 years ago. The early people of the area were rovers who hunted and gathered plants and differed from neighboring peoples in weapons and tools. In more modern times the area of Crosby County was inhabited by the Comanches, mounted hunters and warriors who dominated much of the South Plains in the eighteenth and nineteenth centuries until their buffalo-based culture gave way to settlers and superior technology.
United States Army forces commanded by Col. Ranald S. Mackenzie fought the Comanches at the battle of Blanco Canyon in the future county in 1871. The campaign established what became known as the Mackenzie Trail, used by the first settlers in Crosby County in the late 1870s. From 1874 to 1877 buffalo hunters entered the area, where they took part in the slaughter that exterminated the great buffalo herds. The hunts marked the end of an era. In 1876 the Texas legislature formed Crosby County from lands previously attached to the Young and Bexar districts.
The first permanent settler in the area was Henry Clay Smith, who arrived in 1878 and hauled lumber by ox team from Fort Worth to build his "Rock House" in Blanco Canyon; Smith set up a small cattle ranch. In 1879 Paris Cox established a Quaker colony at Marietta on thirty-two sections purchased from the state for twenty-five cents an acre. Ample underground water supported the efforts of the Religious Society of Friends, and Cox helped early settlers by planting corn, oats, sorghum, melons, and vegetables. In 1880 the census counted eighty-two people living in the county, including one black. Only two farms had been established in the county by that time.
The Quaker colony flourished for a while as a cultural and economic center and attracted merchants and settlers; in 1882 the colony established one of the first schools on the high plains. Crosby County was formally organized after elections held in 1886, with Estacado (the new name of the town formerly called Marietta) designated as the county seat. Open-range grazing continued until the mid-1880s, when barbed wire was introduced and small ranchers and farmers began competing for the land. By 1890 the population of the county was 345. As more settlers moved in to establish farms and ranches, the influence of the Quakers declined and the religious orientation of the community was lost. In 1891 Emma became the seat of government. Until the early twentieth century, the county remained dominated by such large ranches as the St. Louis Cattle Company, the Two-Buckle Ranch, the C. B. Livestock Company (founded in 1901) and smaller spreads. Thanks to plentiful grass and sufficient water holes, and despite the lack of rail transportation in early days, the beef-cattle industry thrived. In 1900, 30,618 cattle were counted in Crosby County, and in 1910 holdings were about the same.
The transition from the era of the giant cattle ranch to one of mixed farming and ranching accelerated during the early twentieth century, when many farmers moved into the area to grow cotton. Only 103 acres was devoted to cotton culture in 1900 and only 324 in 1910. Gins were built at Emma in 1908 and at Lorenzo in 1914, and by 1920 more than 45,400 acres in the county was planted in cotton. The arrival of railroads helped to stimulate economic development between 1905 and 1930, and railroad expansion into the county was closely connected to efforts to subdivide and sell old ranchlands to new farmers. In 1908 the Bar-N-Bar Ranch began selling acreage to farmers. Between 1909 and 1911 the Stamford and Northwestern and the Santa Fe railroads laid tracks into the region, but bypassed Crosby County. In 1910 local investors, including the C. B. Livestock Company, which owned 80,000 acres in the county, raised $75,000 to induce the Crosbyton-South Plains and the Santa Fe to build forty miles of track between Lubbock and Crosbyton. Owners of the C. B. Company hoped to use the new railroad connection to help them sell plots of land in the new settlements they planned to establish at eight-mile intervals between Crosbyton and Lubbock. The towns of Cedric, Lorenzo, and Idalou (the last in Lubbock County) were founded as a result. Emma, the county seat, faded away after the railroad was routed five miles to the north of the town. In 1910 Crosbyton became the new county seat. As development proceeded, the population of the county grew. As late as 1910 only 1,765 people lived in Crosby County, but in 1920 the census counted 6,084 residents.
Farming continued to develop rapidly in the county throughout the 1920s, as the number of farms increased to 1,114 in 1924 and to 1,739 in 1929. In 1924 cotton was planted on more than 81,200 acres in the county, and by 1929 more than 133,467 acres was devoted to the fiber. As more farmers acquired land from the breakup of large ranches, sorghum and wheat culture also expanded, and some farmers began fruit production as well. By 1920 more than 15,000 fruit trees were growing in the county, producing mostly apples and peaches (see FRUITS OTHER THAN CITRUS). Poultry production also became a significant part of the local economy during this time; by 1929 farmers in the county owned almost 83,000 chickens, and that year sold more than 395,000 dozen eggs. Meanwhile, livestock continued to be important. Almost 15,000 cattle were counted in Crosby County in 1920, and more than 15,556 in 1929. The county's population figures reflected this farming expansion. By 1930, 11,023 people lived in Crosby County.
The county was hit hard during the 1930s by the Great Depression and Dust Bowl. Cotton production plunged, especially during the drought of 1933–34, and the county lost 451 farms between 1930 and 1940. On the eve of World War II, only 1,288 farms remained in Crosby County, and the population of the county had dropped to 10,046. Federal control programs and the market needs of the war resulted in a general diversification of crop and livestock production, though cotton continued to be an important crop. Soil-conservation projects were another result of lessons learned during the Dust Bowl. The first soil-conservation district in the county was formed in 1941 to assist in crop rotation, soil building, irrigation, mesquite eradication, and terrace building. The mechanization of farms, which had begun in the 1930s, also helped to stimulate new crop production. Machinery was too expensive for most small farmers, however, and its utilization was one significant reason for the demise of family farms that became obvious in Crosby County by the late 1950s and continued afterwards.
For most of the period since World War II the population of Crosby County has slowly declined. It grew from 9,582 in 1950 to 10,347 in 1960. It dropped, however, to 9,085 in 1970, 8,859 in 1980, and 7,304 in 1990. The discovery of oil in the county in 1955 helped to stabilize and diversify the economy. Oil production was about 41,000 barrels in 1956, 113,300 in 1960, 267,700 in 1978, and 734,300 in 1990. By 1991 more than 14,122,000 barrels of oil had been produced in the county since 1955. Crosby County voters have supported Democratic presidential candidates for most of the county's history. Between 1888 and 1992 they voted for Republicans in national elections only three times, in 1928, 1972, and 1984. In 1990 the economic base of the county appeared stable, with truck farming and oil production contributing significantly. Communities included Ralls, Lorenzo, Farmer, Kalgary, Owens, Robertson, and Wake. In 2014 Crosbyton, the county seat, had a population of 1,678. The county's total population was 5,899. For residents and tourists the county offers such attractions as White River Reservoir, Silver Falls, and Blanco Canyon.