1848 - Treaty of Guadalupe Hidalgo ends Mexican War
The Treaty of Guadalupe Hidalgo was the peace treaty that ended the Mexican-American War (1846–1848). The treaty provided for the Mexican Cession, in which Mexico ceded 1.36 million km² (525,000 square miles) to the United States in exchange for USD$15 million. The United States also agreed to take over $3.25 million in debts Mexico owed to American citizens.
The cession included parts of the modern-day U.S. states of Colorado, Arizona, New Mexico, and Wyoming, as well as the whole of California, Nevada, and Utah. The remaining parts of what are today the states of Arizona and New Mexico were later ceded under the 1853 Gadsden Purchase.