Uncasville is an area in the town of Montville, Connecticut. The area traditionally known as Uncasville is a village in southeastern Montville, at the mouth of the Oxoboxo River. The name is now applied more generally to all of the east end of Montville, which is the area served by the Uncasville ZIP code, including the Mohegan reservation in northeastern Montville that is the site of the Mohegan Sun casino resort and the Mohegan Sun Arena.