Alta California, founded in 1769 by Gaspar de Portolà, was a polity of New Spain and after the Mexican War of Independence in 1822, a territory of Mexico. The region included all of the states of California, Nevada, and Utah. Large areas east of the Sierra Nevada and San Gabriel Mountains were claimed to be part of Alta California, to the southeast, beyond the deserts and the Colorado River, lay the Spanish settlements in Arizona. The areas formerly comprising Alta California were ceded to the United States in the Treaty of Guadalupe Hidalgo that ended the Mexican–American War in 1848, two years later, California joined the union as the 31st state. Other parts of Alta California became all or part of the later U. S. states of Arizona, Nevada, Utah, Colorado, and Wyoming. The Spanish explored the area of Alta California by sea beginning in the 16th century. During the following two centuries there were plans to settle the area, none of which were effectively carried out. Ultimately, New Spain did not have the resources nor population to settle such a far northern outpost. To ascertain the Russian threat a number of Spanish expeditions to the Pacific Northwest were launched, the Spanish Crown funded the construction and subsidized the operation of the missions, with the goal that the relocation, conversion and enforced labor of Native people would bolster Spanish rule. The first Alta California mission and presidio were established by the Franciscan friar Junípero Serra, the following year,1770, the second mission and presidio were founded in Monterey. In 1773 a boundary between the Baja California missions and the Franciscan missions of Alta California was set by Francisco Palóu, the missionary effort coincided with the construction of presidios and pueblos, which were to be manned and populated by Hispanic people. The first pueblo founded was San José in 1777, followed by Los Ángeles in 1781, by law, mission land and property were to pass to the indigenous population after a period of about ten years, when the natives would become Spanish subjects. In the interim period, the Franciscans were to act as mission administrators who held the land in trust for the Native residents, the transfer of property never occurred under the Franciscans. As the number of Spanish settlers grew in Alta California, the boundaries, conflicts between the Crown and the Church and between Natives and settlers arose. State and ecclesiastical bureaucrats debated over authority of the missions and they advocated that the Natives owned property and had the right to defend it. Governor Diego de Borica is credited with defining Alta and Baja Californias official borders, Mexico won independence in 1822, and Alta California became a territory of Mexico. The Spanish and later Mexican governments rewarded retired soldados de cuera with large grants, known as ranchos, for the raising of cattle. Hides and tallow from the livestock were the primary exports of California until the mid-19th century, the construction, ranching and domestic work on these vast estates was primarily done by Native Americans, who had learned to speak Spanish and ride horses
Map of N. America showing California when it was part of New Spain. Map dated 1789 from Dobson's Encyclopedia.
Mexico in 1838. From Britannica 7th edition
Map of Mexico. S. Augustus Mitchell, Philadelphia, 1847. New California is depicted with a north-eastern border at the meridian leading north of the Rio Grandeheadwaters.
Map of independent Mexico before 1848, with Alta California in red, showing the northern border established in 1819 by the Adams-Onis Treaty