Mexican-American War

(1846 – 1848)


  • Failing in an attempt to purchase the Southwest from Mexico, The United States declared war on Mexico on May 13, 1846 following the outbreak of hostilities over the disputed Mexico-Texas border.
  • In July and August, the U.S. Navy occupied all California ports without facing organized Mexican resistance. However, American misrule in Los Angeles led to a local Californio rebellion and the armed expulsion of US occupiers from that city.
  • The rebellion spread through most of Southern California and climaxed in early December with the defeat of Gen. Kearney’s American forces by Californio vaqueros (under the leadership of Andres Pico) at the Battle of San Pasqual.
  • Determined to suppress the rebellion, American commanders Stockton and Kearney prepared to recapture Los Angeles. They ordered American Forces under John C. Fremont to march south from Monterey, while another American force under their joint command marched north from San Diego.
  • Realizing Californio forces were heavily outmanned and outgunned, Andres Pico approached Fremont with honorable terms under which the Californios would surrender.
  • Fremont accepted Pico’s terms in principle and the two sides agreed to meet at Campo de Cahuenga on January 13, 1847 to sign the Articles of Capitulation, known as “Capitulation of Cahuenga.” The generous terms of the agreement ended hostilities in California.
  • After the American conquest of Mexico City, the 1848 Treaty of Guadalupe Hidalgo ended the war and ceded California and the American Southwest to the United States.