Santa Clarita is the fourth largest city in Los Angeles County, California, United States. As of the 2005 California Department of Finance estimate, the city population was 167,954. It is located about 35 miles northwest of downtown Los Angeles, and occupies most of the Santa Clarita Valley. It is a notable example of a U.S. edge city or boomburb. The FBI rates it as the sixth safest city in the United States with at least 100,000 inhabitants. (Nearby Simi Valley and Thousand Oaks, in Ventura County, traditionally alternate between the first and second spots on the list.)

Santa Clarita was incorporated in 1987 as the union of several previously existing communities, including Saugus, Valencia, Canyon Country, Newhall, and portions of Castaic. Its principal boundaries are the Golden State and Antelope Valley freeways; their merger in Newhall Pass at the city's southernmost point gives Santa Clarita its distinctive triangular appearance on the map. Unlike many other hybrid cities' districts, communities in Santa Clarita retain a considerable degree of autonomy, to the extent that some of them--Valencia, most notably--are often mistaken for completely separate cities.

Santa Clarita's most notable attractions are the Six Flags Magic Mountain amusement park on the western edge of the city, and the California Institute of the Arts (CalArts), located in Valencia.

As the city is hemmed in by mountains on all sides (the Tehachapis on the north, the San Gabriels on the east, and the Santa Susanas on the south and west) and is primarily reliant on the automobile for transportation, it suffers from chronic smog. It is also prone to wildfires, as demonstrated by the destruction of large undeveloped areas around the city during blazes in 2003 and 2004.