Merrimack River

The Merrimack River is a 117-mile river that starts where the Pemigewasset and Winnipesaukee rivers meet in Franklin, New Hampshire. It flows south into Massachusetts and then northeast to the Gulf of Maine at Newburyport. It drains a basin of about 5,010 square miles, roughly 3,550 square miles of it in New Hampshire. The upper segment runs about 30 miles through Franklin, Northfield, Boscawen, Canterbury and Concord to Garvins Falls in Bow. Below that, the river passes Hooksett, Manchester, Merrimack and Nashua. The upper and lower New Hampshire segments, nearly 45 miles in total, were added to the New Hampshire Rivers Management and Protection Program in June 1990.

Public access in New Hampshire is spread among the New Hampshire Fish and Game Department, towns, cities and the utility PSNH. Launches include the Merrimack County Boat Launching Facility and Boscawen Town Park in Boscawen, the Sewalls Falls sites in Concord, Lambert Park and Riverside Park in Hooksett, Stark Landing and Arms Park in Manchester, and the Greeley Boat Ramp in Nashua. Canoeing is a popular activity on the upper river. That stretch offers quickwater and flatwater, plus short stretches of whitewater such as the rapids near the breached dam at Sewalls Falls.

The Sewalls Falls dam in Concord is the longest timber crib dam in the world and is credited as the oldest hydroelectric dam in the country. The upper river is a cold-water fishery with at least 19 resident species. Fish and Game regularly stocks the Sewalls Falls area with brook and rainbow trout. The river is also part of the Anadromous Salmon Restoration Program.