The area that is now Upton County was traversed during the early nineteenth century by Comanches and Apaches, who competed for hunting grounds in the area. Both tribes were superior horsemen, capable hunters of buffalo and other game, and relentless raiders of their neighbors. Despite their considerable achievements in material culture and adaptation to their environment, the Indians lost their domination of the region to the United States Army and the advancing tide of white settlers in the 1870s and 1880s. In the 1860s the Chihuahua Trail from Mexico to Indianola, Texas, a significant trading route, crossed the region, as did the route of the Butterfield Overland Mail (1858-61), and the Goodnight-Loving Trail. Originally part of the Bexar Territory, the area was part of Tom Green County from 1874 until 1887, when Upton County was established. A bill was presented to the Nineteenth legislature on March 11, 1885 to divide the western portion of Tom Green County into Ward, Crane, Upton, Ector, Winkler, Loving. Thereby creating six new counties.
The county of Upton is named in honor of Col John C Upton who was killed at the head of his regiment before the evacuation of Richmond
In the fall of 1911 the Kansas City, Mexico and Orient Railway reached the townsite of Rankin, and by January 1912 most of the people living in Upland had moved to Rankin. The county's population soon was concentrated at or near Rankin, and after 1913 the town's school system served the entire county. Rankin became the county seat in 1921.
In 1926 George McCamey's wildcat brought 700 hopeful people to the area and established a new town in the southwest corner of Upton County named for the oil discoverer. The opening of the Yates oilfield especially helped to develop Upton County's economy. The Yates field actually lies in Crockett and Pecos counties, but Rankin developed as the supply and oil service center for the rich district and boomed as a result. McCamey field operators gained a railroad spur from the Santa Fe Railroad, which had taken over the Orient Railroad, to aid development and encourage growth of the new town. By late 1927 several thousand people lived in McCamey. Water had to be freighted from Alpine, 100 miles distant, and was sold at one dollar per barrel until 1929, when good water from the Trinity sands wells seventeen miles away was piped into the town. (Source Unknown)