The Fowler River is a 6.1 mile long (9.8 km) river located in central New Hampshire in the United States. It is an inflow to Newfound Lake, part of the Pemigewasset River and therefore Merrimack River watersheds. Below Bog Brook, the Fowler River is subject to the New Hampshire Comprehensive Shoreland Protection Act. The river begins as Clark Brook on the east slopes of Mount Cardigan in the town of Alexandria, New Hampshire, dropping over Welton Falls. The brook becomes the Fowler River with the juncture of Chesley Brook from the north, at which point the river valley widens and begins to support small agricultural operations. The Fowler River flows southeast to a junction with Bog Brook, where it turns north and flows one mile to Newfound Lake.