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 2010 census was 5,202.

Saranap has had numerous opportunities to be annexed as either part of Lafayette, or of Walnut Creek. These have been largely resisted by the occupants, whose land use is governed by county rules. These include the ability to keep small aviaries and bees, which can be highly restricted by law in surrounding cities, and in newer neighborhoods by restrictive covenants. As the local school district is independent of these city boundaries, and some of the cities impose additional parcel taxes, residents have little incentive to change the status quo. Only a minor addition was made to Lafayette from Saranap in recent decades, adding only one more street and being largely motivated by marginally superior housing values associated with the city of Lafayette.