The Wepawaug River is a stream in New Haven County in the U.S. state of Connecticut.

In Orange, dams form the Wepawaug Reservoir, managed by the South Central Connecticut Regional Water Authority and Lake Wepawaug.

In Milford, dams form the Upper and Lower Lagoons.

English settlers built a grist mill by the river in 1640.

[3] Another mill on the river in Orange made fabric for union soldiers’ uniforms during the American Civil War.