The Isle of Portland is a tied island, 6 kilometres (4 mi) long by 2.7 kilometres (1.7 mi) wide, in the English Channel. The southern tip, Portland Bill, lies 8 kilometres (5 mi) south of the resort of Weymouth, forming the southernmost point of the county of Dorset, England. A barrier beach called Chesil Beach joins Portland with mainland England. The A354 road passes down the Portland end of the beach and then over the Fleet Lagoon by bridge to the mainland. The population of Portland is 13,417.

Weymouth is a sea-side town and civil parish in the Dorset district, in the ceremonial county of Dorset, on the English Channel coast of England. Situated on a sheltered bay at the mouth of the River Wey, 11 km (7 mi) south of the county town of Dorchester, Weymouth had a population of 53,427 in 2021. It is the third-largest settlement in Dorset after Bournemouth and Poole. The greater Weymouth urban area has a population of 72,802.