Area code 909 serves parts of Southern California’s Inland Empire, including San Bernardino, Ontario, and Chino. Established in 1992 from a split with 714, the region has seen major growth as a suburban extension of Los Angeles. It was overlaid by 840 in 2021, requiring ten-digit dialing. The Inland Empire is known for logistics, warehousing, and rapid residential development. Area code 909 has become an identifier of the working-class communities east of L.A., often referenced in Southern California culture and music.