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Piscataqua River

New Hampshire and Maine's Natural Boundary

The Piscataqua River flows 12.25 miles to the Gulf of Maine through the towns of Eliot and Kittery, Maine, and Dover, Newington, Portsmouth, New Castle, and Rye, New Hampshire, functioning as the state border between these two states. The river gets its name from the Abenaki word meaning, "a river with a strong current."


Drainage: 1,495 square miles
Drinking water source for: None
Receives wastewater from: Portsmouth, Kittery, Newington
Significant water features: Brave Boat Harbor, Cocheco River, Salmon Falls River

Watershed Description

The main stem of the Piscataqua River begins at the confluence of the Salmon Falls and Cocheco Rivers. It collects Spruce Creek, and several rivers: Great Works, Salmon Falls, Bellamy, Winnicutt, Squamscott, Lamprey, Oyster, and Exeter. The Piscataqua empties into the Gulf of Maine at Portsmouth Harbor. 

Shipping along the river is very active, with several million tons of cargo entering each year for New Hampshire, eastern Vermont, and southern Maine. Items include petroleum products, rubber and plastics, iron and steel scrap, salt, limestone, gypsum, and fish products. The harbor is used by submarines from the Portsmouth Naval Shipyard on Seavey Island in Kittery and for fuel deliveries to Pease International Tradeport in Newington. Additionally, Portsmouth Harbor is used extensively by a large lobster fishing fleet, charter fishing vessels, commercial fishermen, excursion boats, and local and transient vessels based at or visiting about 20 boating facilities. 

The main stem of the river is densely developed. High levels of impervious surface contribute to increased flow of stormwater into the river. Water quality concerns arise from sewage discharge into the watershed as well as contamination from the shipyard and other industrial uses.

Despite the dense settlement, numerous small parcels of municipal and privately managed conservation land are located throughout the watershed, as well as several state sites and a portion of the Rachel Carson National Wildlife Refuge. Many areas within the watershed provide significant habitat for inland and coastal wading birds and waterfowl, as well as a small area of nesting seabirds. Additionally, several areas provide valuable habitat for wintering deer, the rare New England cottontail, and the endangered bitternut hickory, spotted wintergreen, and scarlet oak. 

Local Information

Conservation Organization

Towns in Watershed

Eliot, Kittery, Dover, New Castle, Newington, Portsmouth, Rye


Piscataqua Region Estuaries Partnership

The goals of PREP are to improve the water quality and overall health of the region’s estuaries as well as encourage locals and visitors to help protect and preserve the places they all love. They aim to achieve these goals by sustaining a long-term monitoring program that assesses estuarine health and by developing support for the implementation of management plans by working with the public, local government, and other stakeholders.

Learn More About PREP