Cohasset Harbor is located about ten miles south of Boston Harbor. It is used extensively by recreational and small commercial craft.

The earliest work in the harbor, completed in 1904, consisted of a channel and turning basin four feet deep and 60 feet wide in the inner harbor. The present project consists of an anchorage seven feet deep and about 18 acres in area in the inner harbor; a channel, eight feet deep and 90 feet wide, extending from the anchorage to the outer harbor; and three six-foot-deep anchorages that total 12.6 acres in area. These anchorages are located in Cohasset Cove (3.9 acres); Bailey Creek (5.4 acres); and the vicinity of Government Island Cove (3.3 acres).

The channel and seven-foot-deep anchorage were authorized by Congress in 1945 and completed in 1960. The three six-foot-deep anchorages were completed in 1968 as a small project under Section 107 of the Continuing Authorities Program.