In what year did the U.S. acquire New Mexico territory from Mexico?

The acquisition of New Mexico territory from Mexico occurred in 1848 as a result of the Treaty of Guadalupe Hidalgo. This treaty was signed at the end of the Mexican-American War, which lasted from 1846 to 1848. Under this treaty, Mexico ceded a significant portion of its northern territories to the United States, including present-day New Mexico, Arizona, California, Nevada, Utah, and parts of Colorado and Wyoming. The year 1848 is significant as it marked the formal transfer of this territory, shaping the future expansion of the United States and its development.

The other years listed do not relate directly to the acquisition of New Mexico. For example, 1821 marks the year Mexico gained its independence from Spain, while 1861 and 1877 fall outside the timeline of territorial acquisition from Mexico.