Historically home to the Kumeyaay people, San Diego was the first site visited by Europeans on what is now the West Coast of the United States. Upon landing in San Diego Bay in 1542, Juan Rodríguez Cabrillo claimed the entire area for Spain, forming the basis for the settlement of Alta California 200 years later. The Presidio and Mission San Diego de Alcalá, founded in 1769, formed the first European settlement in what is now California. In 1821, San Diego became part of the newly-independent Mexico, which reformed as the First Mexican Republic two years later. In 1850, it became part of the United States following the Mexican–American War and the admission of California to the union.

Who claimed the San Diego Bay area for Spain in 1542?