Description
Heads in Lower Mystic Lake and flows SE for 7 miles to join the Chelsea River to form Inner Boston Harbor 0.7 mi NW of East Boston; Cities of Boston, Chelsea, Everett, Medford, Somerville, and Town of Arlington.
History
"Mystic" is derived from the Indian words "Missi" meaning "great" and "tur," meaning "tidal river"; hence "The Great River" (Steel, 1932).