The Barnegat Bay estuary covers over 42 miles of shoreline from the Point Pleasant Canal to Little Egg Harbor Inlet and is protected from the open ocean by a system of barrier beaches and dunes. The flow of fresh water from rivers, creeks and groundwater into the bay produces the special conditions that are important for the survival of crabs, fish, birds, and other wildlife. This water comes from areas inland from the coast but still affects the quality of the bay waters. The entire area of this drainage system into the bay is known as a "watershed."

Over 500,000 people live within the Barnegat Bay watershed, which includes nearly all of Ocean County. That population doubles in the summer as people flock to the shore from nearby Philadelphia, New York, and other parts of New Jersey. The continued economic health of the Barnegat Bay watershed is dependent on the continued health and natural beauty of its waters.

The Barnegat Bay watershed is a 660 square mile area encompassing all of the land and water in Ocean County, as well as parts of Monmouth County. It stretches to the east as far as the barrier islands and extends to the west as far as Plumsted Township; it’s bounded on the north by Point Pleasant Canal and on the south by Little Egg Harbor Inlet. The watershed varies from coastal dunes and marshes (much of which have been heavily developed) to interior Pine Barrens habitats protected from extensive development within the Pinelands. This area is called the Barnegat Bay watershed because all of the water within this area drains to the Barnegat Bay.