Feb 2, 1848: The Treaty of Guadalupe Hidalgo "ended the Mexican-American War (1846–48). By its terms, Mexico ceded 55% of its territory, including parts of present-day Arizona, California, New Mexico, Texas, Colorado, Nevada, & Utah, to the US."

The Treaty of Guadalupe Hidalgo courtesy of the National Archives: https://www.docsteach.org/documents/document/treaty-guadalupe-hidalgo #history #CAhistory