Charles River

Charles River
The Longfellow Bridge crossing over the Charles River, in winter
Country	United States
State	Massachusetts
Cities	Hopkinton, Cambridge, Boston
Source	Echo Lake
- location	Hopkinton, Massachusetts, United States
- elevation	350 ft (107 m)
- coordinates	42°11′34″N 71°30′43″W / 42.19278°N 71.51194°W / 42.19278; -71.51194
Mouth	Boston Harbor
- location	Boston, Massachusetts, United States
- elevation	0 ft (0 m)
- coordinates	42°22′14″N 71°3′13″W / 42.37056°N 71.05361°W / 42.37056; -71.05361Coordinates: 42°22′14″N 71°3′13″W / 42.37056°N 71.05361°W / 42.37056; -71.05361
Length	80 mi (129 km)
Basin	308 sq mi (798 km2)
Discharge
- average	302 cu ft/s (9 m3/s)
- max	4,150 cu ft/s (118 m3/s)
- min	0.1 cu ft/s (0 m3/s)
Charles, Mystic, and Neponset river watersheds

The Charles River (sometimes called the River Charles or simply the Charles) is an 80 mi (129 km) long river in eastern Massachusetts. From its source in Hopkinton the river flows in a northeasterly direction (after first coursing due south through Milford), traveling through 23 cities and towns before reaching the Atlantic Ocean at Boston.

The Charles River is fed by approximately 80 streams and several major aquifers as it flows 80 miles (129 km), starting at Teresa Road just north of Echo Lake (42°12′54″N 71°30′52″W / 42.215°N 71.514444°W / 42.215; -71.514444) in Hopkinton, passing through 23 cities and towns in eastern Massachusetts before emptying into Boston Harbor. Thirty-three lakes and ponds and 35 communities are entirely or partially part of the Charles River drainage basin. Despite the river's length and relatively large drainage area (308 square miles; 798 km²), its source is only 26 miles (42 km) from its mouth, and the river drops only 350 feet (107 m) from source to sea. The Charles River watershed contains over 8,000 acres of protected wetlands, referred to as Natural Valley Storage. These areas are important in preventing downstream flooding and providing natural habitats to native species.

Brandeis University, Harvard University, Boston University, and the Massachusetts Institute of Technology are located along the Charles River. Near its mouth, it forms the border between downtown Boston and Cambridge and Charlestown. The river opens into a broad basin and is lined by the parks of the Charles River Reservation. On the Charles River Esplanade stands the Hatch Shell, where concerts are given in summer evenings. The basin is especially known for its Independence Day celebration. The middle section of the river between the Watertown Dam and Wellesley is partially protected by the properties of the Upper Charles River Reservation and other state parks, including the Hemlock Gorge Reservation, Cutler Park, and the Elm Bank Reservation.