city, Los Angeles county, southern California, U.S. Situated along the Santa Clara River in the Santa Clarita valley between the San Gabriel (San Gabriel Mountains) and Santa Susana mountains, it lies 35 miles (55 km) northwest of central Los Angeles. It consists of several communities, including Canyon Country, Newhall, Saugus, and Valencia, that voted to incorporate in 1987.

Originally inhabited by the Tataviam (Fernandino) Indians, who arrived in the 5th century AD, the area was explored in 1769 by Gaspar de Portolá (Portolá, Gaspar de), who named the region Santa Clara for its river; however, the name Santa Clara had already been given to an area in the San Francisco Bay area, so to avoid confusion the region later took the diminutive form Santa Clarita (“Little Santa Clara”). The Spaniards built an agricultural outpost in the valley in the early 19th century, and eventually the territory became part of the Rancho San Francisco land grant to Antonio del Valle in 1839. Del Valle developed the area into a cattle- and sheep-ranching centre, but the economy was devastated in the 1860s by a severe drought. The discovery of gold in the valley in 1842 brought numerous prospectors, though production dwindled by the end of the decade. Oil became an important industry, and California's first refinery was built there in 1876. Also in 1876, the railway connected the valley with Los Angeles and San Francisco. Communities in the valley subsequently sprung up and were punctuated by saloons and railroad shops. With the advent of the movie industry, westerns began to be filmed in the area; film star William S. Hart (Hart, William S.) built an estate there, and later singer-actor Gene Autry's ranch was the site of numerous movies and television series. Disaster struck the valley in 1928 when a dam burst, killing nearly 500 people.

The contemporary city is largely residential, but there are some biotechnology, manufacturing, aerospace, and other high-technology businesses; the largest single employer is Six Flags Magic Mountain amusement park, which opened in 1971. The city is the seat of the California Institute of the Arts (1961) and several other colleges. The William S. Hart Ranch and Museum contains art and exhibits with western themes. Castaic Lake is a popular recreational area north of the city. Santa Clarita is flanked by Angeles (north and east) and Los Padres (west) national forests. Inc. 1987. Pop. (1990) 110,642; (2000) 151,088.