An Overview of Massachusetts's Rivers, Lakes, Reservoirs & Bays

Largest and Most Notable Rivers & Lakes

Massachusetts spans several major basins. To the west, the Connecticut River drains the Pioneer Valley with tributaries like the Deerfield, Millers, Chicopee, Westfield, Ware, and Swift. The Housatonic and Hoosic flow south from the Berkshires. In the northeast, the Merrimack (with the Nashua, Shawsheen, and Concord/Assabet/Sudbury system) meets the Atlantic at Newburyport. Greater Boston is crossed by the Charles, Mystic, and Neponset. Southeast Massachusetts features the Taunton and Blackstone systems and low‑gradient coastal rivers. Major lakes and reservoirs include Quabbin Reservoir (primary MWRA supply), Wachusett Reservoir, Lake Quinsigamond, Lake Cochituate, Onota and Pontoosuc (Berkshires), Otis Reservoir, Webster Lake (Chaubunagungamaug), the Assawompset–Quittacas pond complex, and numerous Cape Cod kettle ponds.

Water Sources & Flow

Snowmelt and spring rains dominate seasonal flow. Glacial deposits created thousands of great ponds and kettle lakes, especially on Cape Cod and the South Shore. The MWRA system (Quabbin–Wachusett) supplies metro Boston; fish passage restoration continues on the Connecticut, Merrimack, and coastal rivers.

Navigation, Flooding & Shoreline

Boston Harbor and the Cape Cod Canal are key navigation corridors. Flood hazards arise from nor’easters, hurricane remnants, and ice‑jam events on interior rivers; coastal communities manage erosion and sea‑level‑rise impacts along Massachusetts Bay, Cape Cod Bay, and Buzzards Bay.

Recreation

Rowing and paddling on the Charles and Connecticut; whitewater on the Deerfield; sailing on Boston Harbor and Buzzards Bay; flatwater on Quabbin, Wachusett, Quinsigamond, and Cape Cod kettle ponds; beach and bay access along Vineyard and Nantucket Sounds.

Massachusetts Rivers, Lakes, Streams, Reservoirs, Bays and Water Features

Connecticut River (MA reach), MA Deerfield River, MA Millers River, MA Chicopee River, MA Westfield River, MA Ware River, MA Swift River, MA Green River (Deerfield trib.), MA Housatonic River (MA reach), MA Hoosic (Hoosac) River, MA Merrimack River (MA reach), MA Nashua River (North & South Branches), MA Squannacook River, MA Nissitissit River, MA Shawsheen River, MA Concord River, MA Assabet River, MA Sudbury River, MA Ipswich River, MA Parker River, MA Saugus River, MA Charles River, MA Mystic River, MA Malden River, MA Neponset River, MA Monatiquot River, MA Weymouth Fore River, MA Taunton River, MA Nemasket River, MA Mill River (Taunton), MA Three Mile River, MA Blackstone River (MA reach), MA Mumford River, MA Ten Mile River (MA/RI), MA Westport River (East & West Branch), MA Acushnet River, MA Weweantic River, MA Wareham River, MA Jones River (Kingston), MA North River (Scituate), MA Indian Head River, MA South River (Marshfield), MA Agawam River, MA Mashpee River, MA Bass River (Cape Cod), MA Herring River (Wellfleet), MA Quashnet River, MA Pamet River, MA Quabbin Reservoir, MA Wachusett Reservoir, MA Lake Quinsigamond, MA Lake Cochituate (North/Middle/South), MA Webster Lake (Chaubunagungamaug), MA Onota Lake, MA Pontoosuc Lake, MA Otis Reservoir, MA Cheshire Reservoir (Hoosac Lake), MA Hamilton Reservoir, MA Tully Lake, MA Lake Wyola, MA Laurel Lake (Lee/Lenox), MA Goose Pond (Lee), MA Walden Pond, MA Spy Pond, MA Horn Pond, MA Fresh Pond (Cambridge), MA Mystic Lakes (Upper/Lower), MA Ashmere Lake, MA Shaw Pond (Becket), MA Lake Monomonac (MA/NH), MA Congamond Lakes (MA/CT), MA Quaboag Pond, MA Quacumquasit (South) Pond, MA Assawompset Pond, MA Pocksha Pond, MA Great Quittacas Pond, MA Little Quittacas Pond, MA Great Herring Pond, MA Long Pond (Freetown–Lakeville), MA Cape Cod kettle ponds (group), MA Long Pond (Brewster/Harwich), MA Scargo Lake (Dennis), MA Cliff Pond (Brewster), MA Flax Pond (Brewster), MA Great Pond (Wellfleet), MA Great Pond (Eastham), MA Mashpee–Wakeby Pond, MA Johns Pond (Mashpee), MA Santuit Pond (Mashpee), MA Boston Harbor, MA Massachusetts Bay, MA Cape Cod Bay, MA Buzzards Bay, MA Vineyard Sound, MA Nantucket Sound, MA Salem Sound, MA Ipswich Bay, MA Plymouth Harbor, MA Duxbury Bay, MA Barnstable Harbor, MA Lewis Bay (Hyannis), MA Pleasant Bay (Chatham/Orleans), MA Waquoit Bay, MA Wellfleet Harbor, MA Provincetown Harbor, MA Mount Hope Bay (MA/RI), MA Cape Cod Canal (waterway), MA