Cohasset, a town of Norfolk co., Massachusetts, on the South Shore railroad, 15 m. S. E. of Boston; pop. in 1870, 2,130. It borders N. E. and E. on Massachusetts bay, and is surrounded on all other sides by Plymouth co., being separated on the west by Hingham from the main body of Norfolk co. The peninsula of Nantasket, constituting the main portion of the town of Hull, and forming the S. E. side of Boston harbor, projects N. W. from Cohasset about 5 m., and contains Nan-task et beach, 4 m. in length, which is much resorted to for its beauty, fine shell fish, sea fowl, and good bathing. The coast of Cohasset is very rocky, and is noted as the site of Minot's ledge lighthouse. The Conohasset river, which anciently formed the boundary between Plymouth and Massachusetts colonies, flows through a portion of the town. In the S. W. part is a pond of 90 acres, abounding in fresh-water fish. The situation of the town is delightful and romantic, and its ready access from Boston has rendered it a popular summer resort. The inhabitants are chiefly engaged in mackerel fishing and the coasting trade.

Cohasset until 1770 formed a part of Hingham, and was called Conohasset, an Indian name signifying a fishing promontory.