Belfast Harbor in Belfast is located at the mouth of the Passagassawakeag River, which empties into Penobscot Bay, about 18 miles north of Rockland and 40 miles east of Augusta. The harbor, an important shipping center in the early 1800s, is home port to tugs which service commercial vessels, notably at Searsport Harbor. It is also a small fishing port and recreational boating harbor.

Original work in the harbor, completed in 1879, involved constructing a pier on Steels Ledge in the outer harbor and dredging an area in front of the main wharves to a depth of 10 feet.

The present project was completed in 1897. It consists of a 15-foot-deep channel, with a minimum width of 220 feet, extending from the harbor entrance off Pattersons Point to an area across from the wharves in Belfast and anchorage areas on the northeast and southwest sides of the channel. The anchorage on the east side of the channel, at the mouth of the Goose River, is eight feet deep; the anchorage on the channel’s west side is 13 feet deep.