The Congdon River is a river in the U.S. state of Rhode Island, in the Big River State Management Area and immediately south. It flows approximately 3 km (2 mi). There are three dams along the river's length: at Rathbon Pond, Money Swamp Pond, and at Millbrook Pond. The river's crossing at Congdon Mill Road is the former site of a grist mill and later a sawmill, and is named after Joseph Congdon, the mill's owner.