Contra Loma Regional Park is a 780-acre (320 ha) 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 (32 ha) 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 East Contra Costa County. The reservoir is available for year-round fishing and a lifeguarded swim lagoon for summertime swimming. Biking is fine.