Castletown is a small village in Underhill on the Isle of Portland in Dorset. It is located close to Fortuneswell, on the shores of Portland Harbour, and includes a sandy beach, as well as one of Port
Castletown and Portland Harbour in 2006, seen from The Verne. The National Sailing Academy and Portland Castle are on the left. The large buildings in the foreground are former naval buildings, now (2025) partially converted to luxury flats.