Created on September 9, 1850 as part of the Compromise of 1850, the Utah Territory spanned most of what is now the states of Utah and Nevada as well as portions of Colorado and Wyoming. Part of the impetus for its creation was the large number of Mormons who had settled around the Great Salt Lake and sought admission to the Union as the state of Deseret, which was sometimes used as an alternate name for the territory. Mormon influence remained strong after the U.S. Congress created the Utah Territory, and Mormon leader Brigham Young was appointed first governor of the territory by President Millard Fillmore. In 1861, following the settlement of many non-Mormons in the eastern and western portions of the territory, a large portion of the west was designated as the Nevada Territory, all of the land in current day Colorado was ceded to the Colorado Territory and part of the section in Wyoming was ceded to the Nebraska Territory. Another portion of the western part of the Territory was ceded to the Nevada Territory in 1862. The territorial capital was originally located at Fillmore in 1851 but moved to Salt Lake City in 1856.
“An Act to Establish a Territorial Government for Utah,” 9 September 1850, Statutes at Large of the United States 9 (1862):453-58; Glen M. Leonard, “The Mormon Boundary Question in the 1849-50 Statehood Debates,” Journal of Mormon History 18 (Spring 1992): 114-36; Journal of the Executive Proceedings of the Senate of the United States of America (Washington, DC: Government Printing Office, 1887), 8:252, 266; “An Act to Organize the Territory of Nevada,” 2 March 1861, Statutes at Large of the United States 12 (1863):209-14; “An Act to Organize the Territories of Nebraska and Kansas,” 30 May 1854, Statutes at Large of the United States 10 (1855):277-90; “An Act to Provide a Temporary Government for the Territory of Colorado,” 28 February 1861, Statutes at Large of the United States 12 (1863):172-77; “An Act to Extend the Territorial Limits of the Territory of Nevada,” 14 July 1862, Statutes at Large of the United States 12 (1863):575; Patricia Lyn Scott, “Fillmore,” Allan Kent Powell, ed., Utah History Encyclopedia (Salt Lake City: University of Utah Press, 1994), 187–88.