Montville is in New London County. The villages of Chesterfield, Mohegan, Oakdale, and Uncasville are located within the town; (the latter two have their own ZIP codes.) The Mohegan Sun casino resort is nearby.
For defense against the Pequot, the Mohegan sachem Uncas had established a fortified village on a promontory above the Thames River within what is now Montville. The Mohegan village, now known as Fort Shantok, was protected on the inland side by palisades first built in about 1636 at the time of the Pequot War, rebuilt during wars with the Narragansett people circa 1653–1657, and rebuilt again at the time of King Philip's War (1675–1676).