On May 11, 1846, President Polk asked Congress to declare war on Mexico.
The Treaty of Guadalupe Hidalgo ended the Mexican War; it was signed
on February 2, 1848. By this treaty, the United States gained California, Arizona, and Texas, north of the
Rio Grande. The U.S. paid Mexico $15,000,000 and offered U.S. citizenship to any Mexicans who lived in
the new territory.