San Gabriel, founded in 1771, and incorporated in 1913, is a city in the central San Gabriel Valley region of Los Angeles County. It was established when Saint Junipero Serra established Mission San Gabriel Arcangel as the fourth of what would become twenty-one Spanish missions in California. San Gabriel Valley, the San Gabriel River, and the San Gabriel Mountains were all named after the city of San Gabriel and Mission San Gabriel Arcangel commonly referred to as the San Gabriel Mission or Mission San Gabriel.

San Gabriel is located south of San Marino, west of Temple City and Rosemead, east of South Pasadena, and north of Alhambra and Rosemead.

Given the prominence of Mission San Gabriel in the region's history, San Gabriel is commonly called the birthplace of Los Angeles.

Pio Pico, who was appointed as California's governor twice while under Mexican rule, was born and baptized Mission San Gabriel in 1801. Later he was elected as a Los Angeles City councilman.

Today, according to the U.S. Census, more than 50% of the population of San Gabriel is of Asian descent, mostly from China and Taiwan.

East San Gabriel is an unincorporated, census-designated area adjacent to the city of San Gabriel. Likewise, South San Gabriel is an unincorporated, census-designated area adjacent to the city of San Gabriel.