Slave labor underpinned the naval stores industry, and as the industry expanded so did the number of required bondsmen. By the end of the Colonial period Onslow County's population was estimated at 5,000 persons, approximately one-third of whom were slaves. Many slaves were employed in the naval stores industry; others were skilled artisans or worked on area farms.  The Onslow County region, however, did not develop an agricultural economy based on a plantation system, like those that characterized other coastal regions. Natural factors, such as Onslow's small harbors, dangerous shoals, and shifting and shallow inlets, discouraged such plantation style commerce. Instead, the majority of the county's slaveholders lived on small farms, held few slaves, and pursued a combination of subsistence/commercial farming and stock raising. Indian corn, peas, and livestock were the agricultural foundation of the county as the Colonial period drew to a close. In addition, Onslow produced rice, indigo, flour, flax, cotton, hemp, butter, beef, and pork, along with other vegetables and fruit, and a little tobacco for home consumption.

Milling was the only other industry of significance in the county. First gristmills, then sawmills were erected along the banks of Onslow's rivers and their principal tributaries in considerable numbers. With the proximity of the sea and other water sources, fishing and even whaling were also undertaken, but usually only to supplement other economic endeavors. A whaling station was established at Bear Inlet in the early 1800s, at Camp Lejeune's northeastern border.
Marine Corps Base Camp Lejeune