The Mystic River is a 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.