The San Ramon Valley is a region in Contra Costa County and Alameda County, California, east of Oakland, with a population near 130,000 people. The cities of San Ramon, Danville and Alamo as well as the southern edge of Walnut Creek are located in the valley, as are the census-designated places (CDPs) of Camino Tassajara, Blackhawk and Diablo. Interstate 680 serves as the primary transportation route for the area.