Uintah County, Utah: History
Archeological evidence suggests that portions of the Uinta Basin have been inhabited by Archaic peoples and Fremont peoples. By the time of recorded history, its inhabitants were the Ute people. The first known traverse by non-Indians was made by Fathers Domínguez and Escalante (1776), as they sought to establish a land route between California and Spanish America.
The region was claimed by the Spanish Empire as the Alta California division of New Spain (1521-1821) and was later under Mexican control (1821-1848). Neither the Spanish Empire nor Mexico ever had a major presence in the area and their practical control was nominal.
By the early nineteenth century, occasional fur trappers entered the Basin. In 1831-32 Antoine Robidoux, a French trapper licensed by the Mexican government established a trading post near present-day Whiterocks. He abandoned the effort in 1844.
In 1847 a contingent of Mormons under Brigham Young entered the Great Salt Lake Valley to the west of the Uintah region to establish what would become Salt Lake City. In 1861 Young dispatched an exploring party to the Uinta Basin; they reported "that section of country lying between the Wasatch Mountains and the eastern boundary of the territory, and south of Green River country, was one vast contiguity of waste and measurably valueless." Young made no further effort to establish communities in the area but nonetheless included it in their proposed State of Deseret.
The United States took possession under the 1848 Treaty of Guadalupe Hidalgo. In 1861 US President Abraham Lincoln created the Uintah and Ouray Indian Reservation, reserved for the use and habitation of Utah and Colorado Indians. In the 1880s, the Uncompahgre Reservation was created in the southern portion of present-day Uintah County. Ashley Valley was not part of either Reservation; by 1880, enough ranchers and farmers had settled there that the Territorial Legislature created Uintah County from portions of Sanpete, Summit, and Wasatch counties. They established the county seat at Ashley, a now-abandoned settlement three miles north of the present courthouse in Vernal.
Uintah County boundaries were altered in 1892 (Grand County created), in 1917 (adjustments with Duchesne and Summit county boundaries), in 1918 (Daggett County created), and in 1919 (the Daggett boundary line was adjusted). It has remained in its present configuration since 1919.
Gilsonite was discovered in 1888 at Bonanza, in central Uintah County. This mineral was located on Reservation land, and, according to several sources, miners pressured the US government to remove about 7000 acres (11 square miles (28 km2) from the Reservation. Mining and its associated activities rapidly boomed in that area.
The northern boundary of Uintah County originally extended to the north border of Utah. In 1918, the extreme northern portion (lying north of the Uinta Mountain watershed divide) was split off to form Daggett County.