The Bantam River is a two-part, southward-flowing stream located in northwest Connecticut in the United States.

[2] The two sections of the river enter and leave Bantam Lake at points approximately 2,800 feet (850 m) apart on the lake's north shore.

The river drains an area of more than 25,000 acres (10,000 ha) in the towns of Goshen, Litchfield, Morris, and Washington.

Its total course is approximately 18 miles (29 km) in length.

[2] It forms the southern boundary of Mount Tom State Park.