The Mystic River is a 7.0mi river in Massachusetts, in the United States. Its name derives from the Wampanoag word "muhs-uhtuq", which translates to "big river." In an Algonquian language, "Missi-Tuk" means "a great river whose waters are driven by waves", alluding to the original tidal nature of the Mystic. It lies to the north of and flows approximately parallel to the lower portions of the Charles River.The Mystic River has a long history of industrial use and a continuing water quality problem. Encompassing of watershed, the river flows from the Lower Mystic Lake and travels through the Boston-area communities of Arlington, Medford, Somerville, Everett, Charlestown, Chelsea, and East Boston. The river joins the Charles River to form inner Boston Harbor. Its watershed contains 44 lakes and ponds, the largest of which is Spot Pond in the Middlesex Fells, with an area of. Significant portions of the river's shores are within the Mystic River Reservation and are administered by the Massachusetts Department of Conservation and Recreation, which include a variety of recreation areas.
