Harbeson is part of the Seaford, Delaware Micropolitan Statistical Area. Harbeson is an unincorporated community in east central Sussex County, Delaware, United States. It lies at the intersection of U.S. Route 9 and Delaware Route 5, east of the town of Georgetown, the county seat of Sussex County. Its elevation is 36 feet (11 m). Although it is unincorporated, it has a post office, with the ZIP code of 19951.