Marine Corps Base Camp Lejeune is a 246-square-mile (640-square-kilometer) United States military training facility in Jacksonville, North Carolina. Its 14 miles of beaches make the base a major area for amphibious assault training, and its location between two deep-water ports allows for fast deployments. The main base is supplemented by six satellite facilities: Marine Corps Air Station New River, Camp Geiger, Stone Bay, Courthouse Bay, Camp Johnson, and the Greater Sandy Run Training Area. The Marine Corps port facility is in Beaufort, at the southern tip of Radio Island. It is occupied only during military port operations.

Jacksonville is a city in Onslow County, North Carolina, United States. As of the 2020 census, the population was 72,723, which makes Jacksonville the 14th-most populous city in North Carolina. Jacksonville is the county seat and most populous community of Onslow County, which is coterminous with the Jacksonville, NC Metropolitan Statistical Area. Demographically, Jacksonville is the youngest city in the United States, with an average age of 22.8 years old, which can be attributed to the large military presence. The low age may also be in part due to the population drastically increasing over the past 80 years, from 783 in the 1930 census to 72,723 in the 2020 census.