The Spanish colony of Mexico embarked on a war for independence in 1821. Following a successful revolt later that year, the Colony won its freedom from Spain. Alta California, which encompasses present-day California, passed quietly into Mexican control.

Following the Mexican War of Independence, it became a territory of Mexico in April 1822 [ 2 ] and was renamed Alta California in 1824. The territory included all of the present-day U.S. states of California, Nevada, and Utah, and parts of Arizona, Wyoming, and Colorado.