Swartswood Lake (previously called Swartout's Pond) is a freshwater lake located in Stillwater and Hampton townships in Sussex County, New Jersey in the United States.

The lake stretches 3 miles (4.8 km) (north-to-south) and 1 mile (1.6 km) wide (east to west); and has an average depth of 22 feet (6.7 m) with a maximum depth of 42 feet (13 m).

Swartswood Lake is fed by the waters of Neldon's Brook (draining several lakes and Bear Swamp in Stillwater, Hampton, and Frankford townships; and by Indian Creek (or River) which empties Little Swartswood Lake to the north.

The southern end of the lake was dammed by Charles Rhodes, Sr., in 1790 forming a mill pond in the narrow ravine at the lake's outlet, Keen's Mill Brook.

This Sussex County, New Jersey state location article is a stub.