What is now Sun Valley was inhabited by native peoples for 7,000 years prior to the exploration of the Spanish in the 18th century. Gaspar de Portola led an expedition (which included Junipero Serra) in 1769 which was responsible for the series of missions that form a network through California as well as the founding of the Pueblo de Los Angeles.
Toward the end of the 18th Century, Spain granted grazing rights to two areas near what is now Sun Valley: the Rancho San Rafael and Rancho Portesuelo. Other ranchos came into existence about the same time.
Spanish missionaries were charged with civilizing the native peoples who would provide much of the labor involved in maintaining the mission property. In 1797, the Mission San Fernando Rey de Espana was founded and would lend its name to the area in which is was situated: the San Fernando Valley.
Products produced by the missions included wines, olives, figs and pomegranates. Cattle and other livestock were also vital in sustaining the missions.
With Mexican independence from Spain in 1821, Mexico became the controlling power over California and was in charge of land grants. By 1828 the hegemony of the missions came to an end and grants of land were made easier to get, however the Governor of Alta California Manuel Victoria tried to keep the mission system intact. A rebellion in the south against this in 1831 prompted a crackdown by soldiers. However, the rebels achieved their goals and by 1833 the government disestablished the mission system.
Following that came the rise of the rancho as private individuals like Don Vincente de la Osa whose land grant in 1843 became the Rancho Providencia near what is now Sun Valley.
Another similar rebellion arose in 1845 but again the pro-mission governor Manuel Micheltorena was ultimately defeated and replaced by Pio Pico, the final Mexican governor in California.
Because of the looming war between Mexico and the United States, governor Pico began to sell the former mission lands to private owners to raise capital. War eventually came and Mexico was defeated. Pico left California for Mexico and Don Andres Pico signed the surrender of Los Angeles to John C. Fremont at Campo de Cahuenga in what is now Universal City. The treaty of Guadalupe-Hidalgo in 1848 officially ended hostilities between Mexico and the United States and California became U.S. territory.
The 1849 gold rush created a boom in cattle production to satisfy the hunger of miners who entered the territory seeking riches.
After achieving statehood in 1850, new stage and mail routes were established linking Northern and Southern California and between areas near Los Angeles like that which made its way through the Cahuenga Pass, linking up the San Fernando Valley with Los Angeles.
California suffered little during the Civil War years, however the cattle boom had ended by 1855 and new owners purchased lands that had been in Spanish or Mexican hands for decades. Some of the new owners included David Burbank who bought Rancho Providencia and a portion of Rancho San Rafael turning it into a cattle ranch.
What we think of as the modern San Fernando Valley owes its origin to a purchase of 56,000 acres in 1874 by state senator Charles Maclay. With Maclay’s plotting of the town of San Fernando with an eye on luring the Southern Pacific railroad to the area (and the railroad’s arrival shortly thereafter) the San Fernando Valley began its inevitable growth into part of the modern metropolis that is Los Angeles.
The 20th Century brought land owners, developers, businessmen and politicians with names familiar to modern ears: Huntington, Otis, Sherman, Chandler, Van Nuys. A nascent film industry blossomed. The Pacific Electric Railway spanned a swath from the Inland Empire to Ventura.
In 1915, residents of the San Fernando Valley voted to be annexed by the City of Los Angeles. By 1923 the San Fernando Valley as we now it took shape.