Richard L. Saunders offers summary background on indigenous makeup of 19th-century Utah.
Richard L. Saunders, Introduction to Dale Morgan, Shoshonean Peoples and the Overland Trails Frontiers of the Utah Superintendency of Indian Affairs, 1849–1869 (Logan, UT: Utah State University Press, 2007), 14
The valleys and mountains rimming the Great Basin deserts were home to a thinly dispersed but diverse population. The Southern Paiutes, Northern Paiutes (two different peoples) and Western Shoshones, including the Gosiutes, populated the Great Basin deserts west and south of Salt Lake City. The Utes to the east, held mountains and valleys from the Wasatch to the Colorado Front Range. The Bannocks and the Northern and Eastern Shoshonis occupied the Snake River plain between Oregon’s Blue Mountains and the broad swath of the upper Missouri and Green rivers in what is now western and central Wyoming. While the Shoshonis’ heartland fell beyond Utah Territory—bands lived in or frequented Utah’s northern valleys—everything north of Salt Lake City was essentially Shoshoni territory; the so-called Weber Utes, for example, were Shoshoni with an admixture of Gosiutes (actually Shoshoni themselves with a somewhat separate identity) and Utes.