Grabtown Gulch is a valley in San Mateo County, California, with a stream that feeds Purisima Creek. It lies below the former site of Grabtown on Tunitas Road, now part of Purisima Redwoods Open Space Preserve. The gulch was named for Grabtown, once a trading center and lumber camp that began as Gilbert's Camp in the 1880s. Local tradition held that the later name came from residents' reputation for taking land or anything valuable that was not nailed down.