Lake Hopatcong

Lake Hopatcong is the largest freshwater body in New Jersey, United States. About 4 square miles (10 km²) in area, the lake is in the state's northern mountains, north of Netcong and along the border between Sussex and Morris counties. The lake sits within four municipalities: Hopatcong, Jefferson Township, Roxbury Township, and Mount Arlington.

In the 18th century, the lake existed in two separate parts known as the "Great Pond" on the south and "Little Pond" on the north. A natural body of water, the lake has been enlarged by damming of the Musconetcong River, its natural outlet, on the southern side of the lake.