The Musconetcong River is a 45.7-mile-long (73.5 km) tributary of the Delaware River in northwestern New Jersey in the United States.
It flows through the rural mountainous country of northwestern New Jersey. Part of it is a National Wild and Scenic River.
It rises out of Lake Hopatcong, on the border between the borough of Hopatcong in Sussex County and the township of Roxbury in Morris County. It flows through Lake Musconetcong, then flows southwest, past Stephensburg and New Hampton, passing south of Washington then along the southeastern side of the Pohatcong Mountain ridge.
It joins the Delaware at Riegelsville, approximately 10 mi (16 km) south of Phillipsburg.
