Alta California (English: Upper California), also known as Nueva California (English: New California) among other names, was a province of New Spain formally established in 1804. Along with the Baja California peninsula, it had previously comprised the province of Las Californias, but was made a separate province in 1804 (named Nueva California). Following the Mexican War of Independence, it became a territory of Mexico in April 1822 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. The territory was re-combined with Baja California (as a single departamento) in Mexico's 1836 Siete Leyes (Seven Laws) constitutional reform, granting it more autonomy. That change was undone in 1846, but rendered moot by the outcome of the Mexican–American War in 1848, when most of the areas formerly comprising Alta California were ceded to the U.S. in the treaty which ended the war. In 1850, California joined the U.S. as the 31st state.

Spanish soldiers, settlers, and missionaries invaded the homelands of the indigenous peoples of California, people of the Great Basin, and the Pueblo peoples in the establishment of Alta California.

Alta California
S. Augustus Mitchell. Philadelphia · Public domain via Wikimedia Commons

Evidence of Alta California remains in the numerous Spanish place names of American cities such as Monterey, Las Vegas, Los Angeles, Sacramento, San Bernardino, San Diego, San Francisco, San Jose, Santa Ana, and Santa Rosa.

History

Plans for colonization (1697–1769)

Father Eusebio Kino missionized the Pimería Alta from 1687 until his death in 1711. In 1697, a Jesuit expansion into California was funded and the Misión de Nuestra Señora de Loreto Conchó was established that same year. Plans in 1715 by Juan Manuel de Oliván Rebolledo resulted in a 1716 decree for extension of the conquest (of Baja California) which came to nothing. Juan Bautista de Anssa proposed an expedition from Sonora in 1737 and the Council of the Indies planned settlements in 1744, although these plans did not take action.