Marsh Creek State Park is a State Historic Park in east Contra Costa County, California, United States. about 3.3 miles (5.3 km) south of downtown Brentwood. The park, named for the creek flowing through the property, contains the historic stone John Marsh house, ranching buildings, and numerous pre-historic archaeological sites. The creek is named for the ranch's former owner and California pioneer John Marsh (1799–1856), who was a doctor, rancher, landowner and the first non-Hispanic European to settle in what is now Contra Costa County, California. The park is not yet open to the public.