Pequot Indians, a tribe of the Algonquian language family. They lived in Connecticut, east of the Connecticut River. In the Pequot War of 1637, Uncas of the Mohegans revolted against his father-in-law, Sassacus of the Pequots, and joined the English settlers. A force of settlers and Indians led by Captain John Mason attacked a fort at Mystic, killing 600 Pequots. In the Battle of the Great Swamp, during King Philip's War (1675–76), the surviving Pequots were defeated.