Charles (river, United States)
Charles, river, c.60 mi (97 km) long, rising in E Mass. and flowing generally NE to Boston Bay; it separates Boston from Cambridge. Extensive development to the riverfront includes the Esplanade, a series of fishing sites, playgrounds, and walking paths; and the Hatch Shell, where free, open-air concerts are held by the Boston Pops Orchestra. Recreational sailing and canoeing, college rowing, and boat races are common on the river; the Charles River Regatta is held on the last Sunday in October.