The Diablo Valley refers to a valley in the East Bay of the San Francisco Bay Area, to the west/northwest of Mount Diablo. The valley contains the cities of Clayton, Concord, Martinez, the unincorporated area of Pacheco, and Pleasant Hill (home to Diablo Valley College), and most of Walnut Creek. The southern end of Walnut Creek is a part of San Ramon Valley. The Diablo Valley has a diverse population both ethnically, and socio-economically.