[citation needed] Its watershed includes an extensive southern portion of the coastal forested wetlands known as the Pine Barrens.

Its mouth on Delaware Bay is surrounded by extensive salt marshes and has provided a historically important oystering ground.

At Millville it is impounded to form the Union Lake reservoir, approximately 3 miles (5 km) long.

South of Millville it becomes navigable, forming a 10-mile (16 km) estuary that empties into Maurice River Cove on Delaware Bay.

The South Jersey Land and Water Trust focuses on the northern portion of the watershed, from Willow Grove Lake northward.