The Aspetuck River is a 17.0-mile-long (27.4 km) river in the U.S. state of Connecticut. The river rises in the hills located in Huntington State Park in Bethel, with a watershed of approximately 430 acres (170 ha). The river flows generally southerly through Redding, Connecticut to the Aspetuck Reservoir, the Hemlock Reservoir in Easton and Fairfield and finally into the Saugatuck River in Westport, Connecticut and then into the Long Island Sound. It flows through the village of Aspetuck at an average depth of 2.5 feet (0.76 m). The word Aspetuck can be translated as "river originating at the high place" in an Algonquian language.
The Aspetuck Valley Trail is a Blue-Blazed Trail that follows the general course of the river.
The Aspetuck is one of the cleanest rivers in the state, with an AA rating.