The Pleasant River is a 13.1-mile-long (21.1 km) tributary of the Presumpscot River in the U.S. state of Maine. The Pleasant River originates in the town of Gray and parallels U.S. Route 202 as it flows southwesterly through the town of Windham to discharge into the Presumpscot River upstream of the village of South Windham. With the exception of a few cascades over exposed bedrock, the river has a fairly low gradient through the Presumpscot Formation of silt and clay marine mud with localized sandy lenses. Through the center of Windham, the river cuts through end moraines of glacial till, sand and gravel.