Chesil Beach /ˈtʃɛzᵻl/, sometimes called Chesil Bank, in Dorset, southern England is one of three major shingle structures in Britain. Its toponym is derived from the Old English ceosel or cisel, meaning "gravel" or "shingle".
The beach is often identified as a tombolo, although research into the geomorphology of the area has revealed that it is in fact a barrier beach which has "rolled" landwards, joining the mainland with the Isle of Portland, giving the appearance of a tombolo. The shingle beach is 29km long, 200m wide and 15m high. The beach and the Fleet are part of the Jurassic Coast, a UNESCO World Heritage Site, and the location for a 2007 novel, On Chesil Beach by Ian McEwan.
At the eastern end of the beach at the village of Chiswell, against the cliffs of the Isle of Portland, the beach curves round sharply to form Chesil Cove. This part of the beach protects the low-lying village from flooding. The beach has been the scene of many shipwrecks, and as such was named by Thomas Hardy as "Dead Man's Bay". Westwards the shingle forms a straight line along the coast, enclosing the Fleet, a shallow tidal lagoon.
The beach provides shelter from the prevailing winds and waves for the town of Weymouth and the village of Chiswell on Portland.
Varying with the Bank's unbroken increase in height, to 14.7m, above mean high water, the size of the flint and chert shingle varies from pea-sized at the north-west end to orange-sized at the south-east end (by Portland). It is said that smugglers who landed on the beach in the middle of the night could judge "exactly where they were" by the size of the shingle.
There are three owners of the beach. The Crown Estates own the beach from Portland to its boundary stone at Littlesea. The bed of the lagoon and Chesil Beach adjacent to the Fleet, as well as the majority of the land of Upper Fleet to West Bexington, are owned by the Ilchester Estates, who are based north of Dorchester, but also have a local office in Abbotsbury. Finally from West Bexington to West Bay it is owned by the National Trust. The whole of Chesil Beach south from the Portland Bound Stone is registered common land over which there is a right of public access on foot.