Saranap (until 1913, Dewing Park) is a residential census-designated place (CDP) within central Contra Costa County, California. Lying at an elevation of 180 feet (55 m), it is bounded on the south and east by portions of Walnut Creek (including the gated senior residential development Rossmoor) and on the north and west by Lafayette. Saranap's ZIP code is 94595, but is addressed "Walnut Creek, CA" for delivery purposes as this is the postal designated city name used by residents. The community is in telephone area code 925. Saranap's population as of the 2020 census was 5,830.