 It serves chartered organizations and BSA units in Contra Costa County, Lake County, Napa County, Solano County (except the cities of Dixon, Rio Vista, and Vacaville), and the cities of Albany and Berkeley in northern Alameda County.The council is located in BSA Western Region Area III.The Mount Diablo Silverado Council (#023) was formed in 1992 as the result of a merger between the former Silverado Area Council (#038) and the former Mount Diablo Council (#023).