Jacksonville is a city in Onslow County, North Carolina, United States. As of the 2010 United States census, the population was 70,145, which makes Jacksonville the 14th-largest city in North Carolina. Jacksonville is the county seat and most populous community of Onslow County, which is coterminous with the Jacksonville, North Carolina metropolitan area. In 2014, Forbes magazine ranked Jacksonville as the fifth-fastest growing small city in the United States. 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 going up over the past 80 years, from 783 in the 1930 census to 70,145 in the 2010 census.It is the home of the United States Marine Corps' Camp Lejeune and New River Air Station. Jacksonville is located adjacent to North Carolina's Crystal Coast area. On 21 June 2016, the City of Jacksonville, became the first jurisdiction to adopt a paid holiday honoring the 13th Amendment to the United States Constitution, which made slavery in the United States and its territories illegal. The resolution of adoption targets the prevention of the modern slavery epidemic in the form of human trafficking, which includes forcing children to engage in labor and combat.

Topsail Beach is a town in Pender County, North Carolina, United States. The population was 383 at the 2012 census. It is part of the Wilmington Metropolitan Statistical Area.

Pender County is a county located in the U.S. state of North Carolina. As of the 2010 census, the population was 52,217. Its county seat is Burgaw. Pender County is part of the Wilmington, NC Metropolitan Statistical Area.

Duplin County () is a county located in the U.S. state of North Carolina. As of the 2010 census, the population was 58,505. Its county seat is Kenansville.