It rises in northwestern Onslow County and flows SEE, past Jacksonville, where it widens into a tidal estuary approximately 2 mi (3.2 km) wide. As an estuary it meanders through Camp LejeuneMarine Base and enters the Atlantic in Onslow Bay, via the New River Inlet between two barrier islands.
The Intercoastal Waterway crosses the entrance of the river between the coast and the barrier island.