During the mid-19th century, when Mormon pioneers entered Utah territory, the Timpanogos were one of the principal tribes in the region based on population, area occupied, and influence.

Historically, most communication was carried out in Spanish or English, and many of their leaders spoke several dialects of the Numic branch of the Uto-Aztecan language family.

[3] The Shoshone and Ute share a common genetic, cultural, and linguistic heritage as part of the Numic branch of the Uto-Aztecan language family.

[6][better source needed] The shores of Utah Lake became a sacred meeting place for the Timpanogos, Ute, and Shoshone tribes.

The first known Europeans to enter this area were a Spanish expedition of Franciscan missionaries led by Father Silvestre Vélez de Escalante.

Besides this, they gather in the plain grass seeds from which they make atole, which they supplement by hunting hares, rabbits, and fowl of which there is great abundance here.

In 1826, American mountain man Jedediah Smith visited a camp along the Spanish Fork (river) with 35 lodges and about 175 people.

[19] They built several log houses, surrounded by a 14-foot (4.3 m) palisade 20 by 40 rods long (330 by 660 feet [100 by 200 m]) with gates at the east and west ends and a middle deck for the cannon.

The fort, built on the sacred grounds of the annual fish festival, was very close to the main Timpanogos village on the Provo River.

[9][19][22] By January 1850, the settlers at Fort Utah reported the increasing tension to officials in Salt Lake City and requested a military party to attack the Timpanogos.

Eleven Timpanogo warriors surrendered on February 14, but the militia executed them in front of their families and a government surgeon beheaded them after death for research.

[24][better source needed] According to a state of Utah historical website, In 1861, President Abraham Lincoln signed an executive order establishing the original Uintah Valley Reservation in the eastern part of the Utah territory ... Congress ratified the order in 1864 ... A council of the Ute people was called at Spanish Fork Reservation on 6 June 1865.

The treaty provided that the Utes give up their lands in central Utah, including the Corn Creek, Spanish Fork, and San Pete Reservations.

[26][27][better source needed] In 1847, at the time of the Mormon pioneers' arrival, the Timpanogo population has been estimated at about 70,000; their numbers had been dwindling because of competing bands of Shoshone raiders since the early 19th century.

Collins estimated ... that there may have been fifteen to twenty thousand Indians (of all tribes) in Utah prior to the arrival of the first Mormon settlers" in 1847.

Although many historians refer to Sowiette, San-Pitch and their people as Utes, at the time of the Uinta treaty they were known as the Utah Indians or Timpanogos.

This farm was opened about two years ago, under the directions of Agent Hurt, for a band of the Utahs under Chief Arapeen, a brother of San-Pitch ...

They generally inhabit the Wind river country, in Oregon and Nebraska Territories and they sometimes range as far east as Fort Laramie ...

Under the Indian Reorganization Act of 1934 (part of President Franklin D. Roosevelt's New Deal), the Ute bands organized as a unified tribe with a constitution based on the election of a chief and council.

Their documents did not mention the Timpanogos, who believe that the 1950s federal termination of Native American status of the Ute tribe's mixed-blood members should have had no effect on them.

[citation needed][34][35] In Hagen v. Utah (1994), 510 U.S. 399, 421–22, the US Supreme Court agreed with the state that a portion of Uintah Reservation had been reduced by Congressional action since 1985.

Afterward, the state began again to prosecute Ute for offenses in Indian country, apparently to challenge the court ruling.

In 2015 the Appeals Court heard testimony from the Ute Indian Tribe plaintiffs and ruled that this disruptive behavior by the state and county officials had to stop, saying that the issues had been settled for nearly 20 years.

But their relocation by an act of Congress to the existing Uintah Valley Reservation in the 1880s had the legal effect of a treaty recognizing them as a tribe, as noted by the courts.