Smithville Township is one of six townships within Brunswick County, North Carolina, United States. As of the 2000 Census, Smithville Township had a population of 12,019 and a population density of 152 inhabitants per square mile (59/km2). It is a part of the Myrtle Beach metropolitan area.
Smithville Township, occupying 79 sq mi (200 km2) of land and 120.3 sq mi (312 km2) of water, is located on the Atlantic Ocean coast and encompasses the towns of Oak Island, Southport, Caswell Beach, and Bald Head Island. It is the site of the Brunswick Nuclear Generating Station.