Contra Loma Regional Park is a 780-acre regional park in Contra Costa County, California. It is part of the East Bay Regional Parks system. It is located in the city of Antioch and includes an 80-acre reservoir. The U.S. Bureau of Reclamation is updating its long-term plan for the Contra Loma Regional Park and the adjacent Antioch Community Park. The previous plan was written in 1975, before a population boom hit eastern Contra Costa County.