The Isle of Portland is a tied island in the English Channel, 6 kilometres long by 2.7 kilometres wide, 5 miles south of Weymouth. It forms the southernmost point of the county of Dorset, England; it ends with the lighthouse at Portland Bill. A barrier beach called Chesil Beach also joins it to the mainland There are eight settlements on the Isle of Portland... Fortuneswell, Castletown and Chiswell are the villages in Underhill, and Easton, Weston, Southwell, Wakeham and The Grove are on the Tophill plateau.