America Receives Western Territories in Treaty With Mexico After War of 1848

In the wake of America's victory over Mexico in the War of 1848, the Treaty of Guadalupe Hidalgo gives the U.S. official control over a large amount of territory in the West, including that portion already settled by Mormons in the region of Deseret.

This brings the Mormon communities under the political control of the United States government and will lead to numerous political and cultural confrontations in the following decades.