Onslow County area

Population and density of Onslow County

The Census Bureau estimates that 217,175 people lived in Onslow County on July 1, 2025. That ranks #332 of 3,222 county equivalents nationally and #13 of 100 in North Carolina. Since the April 1, 2020 estimates base of 204,475, the population has grown by 12,700 (+6.2%), compared with +7.2% for North Carolina as a whole.

With 762.1 square miles of land, that is 285 people per square mile (110 per km²), placing Onslow County #529 nationally for density and #21 in North Carolina. The median county equivalent has 47 people per square mile; the North Carolina median is 116. Put another way, there are about 2.2 acres of land per resident.

U.S. Census Bureau, Vintage 2025 population estimates. Estimates are revised each year and are not decennial census counts. Density divides the whole population by the whole county’s land area, so it describes an average, not how settlement is distributed within the county. Population sources and methods.

Cities and towns in Onslow County

6 incorporated places lie at least partly in Onslow County. Together they are home to 86,826 people (40%); the other 130,349 (60%) live outside any incorporated place, in unincorporated communities and rural areas.

The largest is Jacksonville city, with 72,732 residents in the county. Among places with at least 1,000 residents in 2020, Holly Ridge town grew fastest since then (+41.6%).

Population: U.S. Census Bureau Vintage 2025 subcounty estimates, counting only the part of each place inside Onslow County. Land: 2026 Census Gazetteer, for the whole place even where it extends into other counties. How communities are listed.

Metropolitan area

Onslow County is a central county of the Jacksonville, NC Metropolitan Statistical Area. Onslow County is the area’s only county equivalent, so the metro area has the same 762.1 square miles of land. By combined land it ranks #312 of 393 metropolitan areas, and #224 by population.

ZIP codes

17 ZIP Code Tabulation Areas have land in Onslow County; 13 of them have most of their land inside the county, and the others mainly cover neighboring areas.

2844528454284602851828521285392854028542285432854428546285472855528572285742858228584

ZIP Code Tabulation Areas are the Census Bureau’s approximations of USPS ZIP Code service areas, from the 2020 Census relationship files. Lighter codes have less than half of their land in this county. Post-office-box and single-address ZIP Codes have no tabulation area.

Counties bordering Onslow County

Onslow County shares a land border with 4 county equivalents. It has more land than 2 of them. The largest neighbor is Pender County (871.3 mi²) and the smallest is Jones County (471.4 mi²). Together with its neighbors, Onslow County forms a block of 3,427.1 mi² of land, of which it holds 22.2%.

How big is Onslow County compared with U.S. states?

Onslow County has less land than any of the 50 states. Rhode Island, the smallest state by land area, has 1,033.9 mi², about 1.4 times as much. North Carolina’s county land could hold about 64 areas the size of Onslow County.

Another way to picture it: the same land area would fill a square about 27.6 miles (44.4 km) on each side. Real county shapes are rarely square, so this is a scale reference rather than a width or driving distance.

State figures are the sums of each state’s county-equivalent land measurements in the same Census release, so states and counties are compared on the same basis. Published state totals can differ slightly because of rounding. Compare all states · Counties bigger than entire states.

What stands out about Onslow County?

Onslow County has more land than 2,077 of the other 3,221 county equivalents in the dataset.

A median is the middle county-equivalent measurement, not the average of the largest and smallest. All three bars use the same linear scale. Very small areas may appear as a thin sliver; the labels retain their values.

Does including water change its rank?

Using land plus water places Onslow County at #951 nationally by total area, 194 places closer to the top than its land rank. The water assigned to this geography moves it ahead of some county equivalents with more land.

Its water share is 15.8%, compared with a national county-equivalent median of 1.2% — 14.6 percentage points higher. This describes the statistical geography’s land/water mix, not flood exposure or developable land.

Closest positions in the national land ranking

These entries sit immediately beside Onslow County in the national ranking. They can be in different states and are not necessarily geographic neighbors.

Calculated from the same Census release as the area table. Total-area order uses original ALAND + AWATER; water shares and chart labels use published square miles. Calculation details.