Greenwich Harbor, located about 2.5 miles east of the New York state line in Greenwich, consists of an outer harbor and three inner coves.

Initial work in Greenwich Harbor was completed in 1905. The features of the present project, completed in 1951, include:

• A 1.4-mile-long, 12-foot deep channel. The channel is 130 feet wide from the outer harbor to the town wharf, then 100 feet wide along the wharf front to a point about 50 feet from the head of the harbor.
• An anchorage area six feet deep and about 12 acres in area north of Grass Island and west of the channel.
• An anchorage area eight feet deep and 21.5 acres in area south of Grass Island and west of the channel.