Alta California

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 union as the 31st state.

The El Camino Real trail established by the Spanish extended from Mexico City west to Santa Fe, and California, as well as east to Florida. To the southeast, beyond the deserts and the Colorado River, lay the Spanish settlements in Arizona. 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.

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.

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.

Don Fernando Sánchez Salvador researched the earlier proposals and suggested the area of the Gila and Colorado Rivers as the locale for forts or presidios preventing the French or the English from "occupying Monterey and invading the neighboring coasts of California which are at the mouth of the Carmel River." Alta California was not easily accessible from New Spain: land routes were cut off by deserts and Indigenous peoples who were hostile to invasion. Sea routes ran counter to the southerly currents of the distant northwestern Pacific. Ultimately, New Spain did not have the economic resources nor population to settle such a far northern outpost.

Spanish interest in colonizing Alta California was revived under the visita of José de Gálvez as part of his plans to completely reorganize the governance of the Interior Provinces and push Spanish settlement further north. In subsequent decades, news of Russian colonization and maritime fur trading in Alaska, and the 1768 naval expedition of Pyotr Krenitsyn and Mikhail Levashov alarmed the Spanish government and served to justify Gálvez's vision.

The Portolá expedition was the first European land-entry expedition into the area that is now California. The missionaries and soldiers encountered numerous Indigenous peoples of the area, who became the primary subjects of the expanding Jesuit and Franciscan missions that were already established in Baja California and Baja California Sur. The expedition first established the Presidio of San Diego at the site of the Kumeyaay village of Kosa'aay, which became the first European settlement in the present state of California. At first contact, the villagers provided food and water for the expedition, who were suffering from scurvy and water deprivation.