Little Harbor is situated between the island of New Castle to the north and Rye to the south. The harbor’s northwesterly end, located at the Bascule Bridge (Route 1B), leads into the southerly end of Portsmouth Harbor. Little Harbor is used today mostly as an access route for recreational and fishing boats and other. small craft based at Sagamore Creek, a popular boating center situated immediately northwest of the harbor. Small boats also use Little Harbor as a refuge.
Commercial sailing schooners operating along the coast at the turn of the century needed a safe harbor of refuge as they waited for moderate tides in Portsmouth Harbor. At that time, Little Harbor was too shallow to accommodate these schooners. The Corps began work in Little Harbor in 1887 and, after several modifications, completed the project in 1903. The project consists of:
- Two stone breakwaters, one on each side of the harbor entrance. The north breakwater, off Jaffrey Point in New Castle, is 550 feet long. The south breakwater, off Frost Point in Rye, is 900 feet long. The breakwaters were completed in 1894.
- A 3,000-foot-long entrance channel, 12 feet deep and 100 feet wide, extending through the harbor to the vicinity of the Bascule Bridge (Route 1B).
- A 12-foot-deep anchorage basin, 700 feet long and 300 feet wide (about 40 acres in area), lying immediately south of the entrance channel.
The commercial sailing schooners for which the project was designed were phased out of existence in the late 1920s.