Saranap (until 1913, Dewing Park)[3] 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.

[4] 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.

The local station, located near the intersection of Tice Valley Boulevard and Olympic Way, was named after the railroad developer's mother, Sara Napthaly.

According to the United States Census Bureau, the CDP has a total area of 1.135 square miles (3 km2), all of it land.