The Isle of Portland is a limestone tied island, 4 miles (6.44 kilometers) long by 1.7 miles (2.74 kilometers) wide, in the English Channel. Portland is 5 miles (8.05 kilometers) south of the resort of Weymouth, forming the southernmost point of the county of Dorset, England. A barrier beach over which runs the A354 road connects it to Chesil Beach and the mainland. Portland and Weymouth together form the borough of Weymouth and Portland. The population of Portland is 12,400.
Portland is a central part of the Jurassic Coast, a World Heritage Site on the Dorset and east Devon coast, important for its geology and landforms. Its name is used for one of the British Sea Areas, and has been exported as the name of North American and Australian towns. Portland stone, famous for its use in British and world architecture, including St Paul's Cathedral.
Portland Harbour, in between Portland and Weymouth, is one of the largest man-made harbours in the world. The harbour was made by the building of stone breakwaters between 1848 and 1905. From its inception it has been a Royal Navy base, and played prominent roles during the First and Second World Wars; ships of the Royal Navy and Allied Pact countries work up and exercise in its waters.