Marine Corps Base Camp Lejeune is home to more than 47,000 Marine and Sailors from around the world. These servicemen and women serve with hundreds of company-size units that compose several major commands aboard base. Marine Corps Base, Camp Lejeune, as an element of the Marine Forces Atlantic supporting establishment, provides the operating forces and Camp Lejeune community support and services that enhance operational readiness and the quality of life. Marine Corps Base provides housing, training and facilities. During exercises, Marine Corps Base provides active and reserve warfighting commands with support such as logistics, transportation and coordination for deployments. Marine Corps Base is also responsible for the resident formal school training of approximately 39,000 Marines and provides job enhancement training for 8,000 Marines and Department of Defense employees annually. Courses range from formal Military Occupational Specialty and computer training to total quality leadership classes.

The base is home to an active duty, dependent, retiree and civilian employee population of nearly 150,000 people. The base generates $2 billion in commerce each year, coming from payrolls and contracts let to support the structure required to train and equip Marines.

The southern portion of Onslow County is home of Camp Lejeune, the US Marine Corps' largest amphibious training facility. Camp Lejeune sits just south of the US Marine Corps New River Air Station one of the largest helicopter stations in the US Marine Corps. New River and Browns Inlets are transitional mixed energy (wave dominated) inlets located in Southeastern North Carolina within the cental Onslow Bay compartment. New River seperates Topsail Island, a 27km developed barrier to the south, from Onslow Beach, a 12km undeveloped barrier owned by the US Marine Corps. Northern Onslow Beach is seperated from Browns Island, a 5.6km undeveloped barrier, by Browns Inlet. Onslow Beach North is not MPF capable since there is no MPF capable port within 92.7 km (50 nm) of the beach. It is not JLOTS capable due to insufficient beach gradient. It is, however, LCAC off-load capable due to average backshore width of 66.4 m (218 ft). Cross-country to partial cross-country exits are available along the entire beach. These exits are too numerous to list individually. Parallel to the beach is a roud that extends 6.3 km (3.4 nm) southwest to New River Inlet and 1.4 km (0.8 nm) northeast to Onslow Beach Road which leads approximately 2.8 km (1.5 nm) north-northeast to Highway 172. There are several buildings and compounds in the hinterland along the road.