The California Campaign (1846–1847), also known as the Conquest of California or Conquest of Alta California by the United States, was an early military campaign of the Mexican-American War that took place in the western part of Mexico's Alta-California Department, in the present-day state of California. On this day in 1847, U.S. Marines under the command of Captain Archibald Gillespies capture Los Angeles and raise the US. Flag over his old headquarters.
