Area: 6,923 square miles;
Population: 26,601 (in 1990);
County seat: Tooele City;
Origin of county name: probably from tule, a Spanish word of Aztec origin, meaning bulrush, a marsh plant;
Principal cities/towns: Tooele City (13,887), Grantsville (4,500), Wendover (1,122);
Economy: defense, transportation, communications, trade, services;
Points of interest: Bonneville Speedway, Deseret Peak Wilderness Area, Ophir Town Hall, Grantsville First Ward, Old Pony Express and Stage Route, Iosepa Cemetery, Great Salt Lake.
Tooele County is Basin and Range country. Most of its towns lie in a broad valley between the mineral-rich Oquirrh Mountains on the eastern border and the Onaqui and Stansbury mountains to the west. The Great Salt Lake Desert covers most of western Tooele County, except the southwest corner where the Deep Creek Mountains rise.
Prehistoric Indian sites have been discovered in the county, but it is the Goshutes, a branch of the Western Shoshone, who claim this harsh environment as their ancestral homeland. Their ingenious use of the limited plant and animal resources of the area amazed the first white travelers. The Goshutes currently have a reservation in Skull Valley.
Tuilla, as it was originally spelled, was one of six counties created in January 1850. Its boundaries were changed a number of times before it achieved its present size as the state's second largest county.
The Mormons herded livestock in Tooele Valley before permanent settlement began in 1849. The early settlers farmed, built gristmills and sawmills, and manufactured salt, charcoal, lime, adobe bricks, and woolen products. Large sheep and cattle herds were developed, and hay and grain became important crops. But mining and smelting, not agriculture, led the county's growth from the 1860s to World War II.
The Rush Valley Mining District, organized in 1864 by soldiers from Fort Douglas, included all of the western Oquirrhs. More than 500 mining claims were located during the first year. Of the mining towns founded in Tooele County, Ophir and Mercur became the most important. Ophir boomed in the 1870s with an estimated population of 6,000 and mines that produced millions of dollars in silver, lead, zinc, and gold. Mercur endured several boom and bust cycles as well as two major fires; with a population estimated as high as 10,000 it flirted briefly with the idea of taking the county seat from Tooele City.
The International Smelting and Refining Company's smelter, built east of Tooele City in 1910, for some sixty years processed ore carried by aerial tramway from the Bingham mine. The plant attracted workers from southern and eastern Europe, diversifying Tooele's ethnic and religious mix. The Tooele Valley Railroad, completed in 1909, served the smelter's needs and provided additional jobs.
Military installations built during World War II boosted the county's population and continue to pump millions of dollars into the local economy. Wendover Air Force Base (now closed) near the Nevada border became an important site for bomber training, at one time employing almost 20,000 military and civilian personnel. Tooele Ordnance Depot (now Tooele Army Depot, or TAD), built in 1942 on a huge tract of land south of Tooele City, served as a major supply, storage, and repair center, employing almost 2,000 civilians in 1944. Activity at TAD peaked during the Korean War and again during the Vietnam conflict. Dugway Proving Grounds, a chemical and biological warfare test center built at the same time, became controversial in the 1970s when a large number of sheep in the area were killed, presumably as a result of nerve gas testing. Today, most of western Tooele County is reserved for military use. Citizens of Tooele County received a major economic blow in 1993 when the Tooele Army Depot was included on a Defense Department list of bases to be closed. Although the closure of the depot will undoubtedly greatly affect the county, citizens and officials are working to mitigate the impact.