Buying land in Onslow County, North Carolina: what to check
Onslow County covers 762 square miles of land and 143 of water in North Carolina, with about 212,954 residents in 2024 (up 4.1% since 2020). The 2020 Census counted 87% of its land as rural and 64% of residents as living in urban areas. Farms operate 11% of the county's land. Below: how much of Onslow County floods, what its soils allow, what farmland is worth and how often it's in drought, from free public data with every source linked.
Onslow County at a glance
Hydric (wetland-type) soils
46%
Above the state's county median (3.2%)
Farm land value, 2022
$6,189/acre
Above the state's county median ($5,848)
What to check before buying land in Onslow County
Ordered by what Onslow County's numbers point to. Every parcel differs, so treat this as where to look first.
1.Budget for a perc test and maybe an engineered septic
USDA rates 88% of Onslow County's mapped soils "very limited" for conventional septic absorption fields and 0% "not limited".
Without city sewer you need a septic permit from the county or state health department. Make the offer contingent on a passing soil or perc test; mound and aerobic systems can cost several times a conventional one.
2.Expect wetlands; map them before you plan
About 46% of Onslow County's mapped soils are hydric (formed under saturated conditions, a federal wetland indicator) and 48% are poorly or very poorly drained (USDA SSURGO).
Open the National Wetlands Inventory mapper at the parcel. Filling or draining a wetland can need a Clean Water Act Section 404 permit, and wet ground limits septic fields and building pads.
3.Put flood checks first in Onslow County
7.2% of the county's area is in the 1%-annual-chance (100-year) floodplain FEMA's National Risk Index uses for inland flooding; under 1% is exposed to coastal flooding; 10% of its mapped soils flood occasionally or frequently.
Look up the FEMA flood zone at the pin, not the parcel's address. If any of the land is in zone A or V, price flood insurance before you offer, ask for an elevation certificate, and check whether the access road floods too.
4.Check the soils if you plan to farm, graze or garden
Farm real estate in Onslow County averaged $6,189 an acre including buildings in the 2022 Census of Agriculture, and 46% of its mapped soils are prime or of statewide importance.
Compare the asking price with recent sales of similar tracts, not the county average, which mixes cropland, pasture, timber and homesites. If an ag tax valuation applies, ask what the rollback taxes would be if you change the use.
5.Confirm legal road access and power
The 2020 Census classified 87% of Onslow County's land area as rural.
Rural tracts are often sold without recorded access or a power line nearby. Get the title company to confirm a recorded easement or public road frontage, and ask the electric co-op what a line extension costs.
6.Find out where the water comes from
At least half of Onslow County was in severe drought (D2) or worse in 12% of the 262 weekly U.S. Drought Monitor maps from 2021 to 2026.
Ask whether the land has a public water connection, an existing well (and its log and yield), or neighbors' well depths from the state well database. For a new well, check permits and typical depth with the state agency first.
Flood zones, wetlands and water in Onslow County
- Area in the 1%-annual-chance (100-year) floodplain
- 7.2%, 49th highest of 100 in North Carolina FEMA National Risk Index
- Area exposed to coastal flooding
- under 1% FEMA National Risk Index
- Mapped soils that flood occasionally or frequently
- 10% USDA NRCS Web Soil Survey (SSURGO)
- Hydric soils (a federal wetland indicator)
- 46% USDA NRCS Web Soil Survey (SSURGO)
- Poorly or very poorly drained soils
- 48% USDA NRCS Web Soil Survey (SSURGO)
- Surface water (lakes, rivers, reservoirs)
- 143 sq mi Census 2024 Gazetteer Files
- Drought on 2026-10-27
- 100% moderate or worse, 85% severe or worse U.S. Drought Monitor county statistics
The floodplain share is the area FEMA's National Risk Index counts as exposed to inland flooding, mostly mapped 100-year flood zones. It says how common flood-prone land is in Onslow County, not whether a given parcel floods. For that, look up the zone at your exact point on the FEMA Flood Map Service Center or run the free check.
Soils and terrain
- Prime farmland
- 15% USDA NRCS Web Soil Survey (SSURGO)
- Prime only if drained, irrigated or protected
- 18% USDA NRCS Web Soil Survey (SSURGO)
- Farmland of statewide importance
- 32% USDA NRCS Web Soil Survey (SSURGO)
- Average slope over 15%
- 0% USDA NRCS Web Soil Survey (SSURGO)
- Very limited for septic absorption fields
- 88% USDA NRCS Web Soil Survey (SSURGO)
- Not limited for septic absorption fields
- 0% USDA NRCS Web Soil Survey (SSURGO)
Shares of Onslow County's soil-surveyed land (about 488,070 acres, open water excluded), using each map unit's dominant condition in USDA's SSURGO soil survey. Soils change within a few hundred feet, so the soil at your building site is what matters.
Farms and land use
- Farms (2022)
- 342 USDA NASS, 2022 Census of Agriculture
- Share of the county's land in farms
- 11% USDA NASS, 2022 Census of Agriculture
- Average farm size
- 155 acres (median 46) USDA NASS, 2022 Census of Agriculture
- Average value of land and buildings
- $6,189 per acre, 45th highest of 100 in North Carolina USDA NASS, 2022 Census of Agriculture
- Cropland
- 33,916 acres USDA NASS, 2022 Census of Agriculture
- Pasture and rangeland
- 3,153 acres USDA NASS, 2022 Census of Agriculture
- Woodland on farms
- 13,851 acres USDA NASS, 2022 Census of Agriculture
- Irrigated land
- 1,070 acres USDA NASS, 2022 Census of Agriculture
Natural hazard ratings
FEMA's National Risk Index rates each hazard for Onslow County relative to every other U.S. county. Overall risk: Relatively High.
- HurricaneVery High
- Winter weatherVery High
- LightningRelatively High
- Coastal floodingRelatively Moderate
- Heat waveRelatively Moderate
- River and inland floodingRelatively Moderate
- Strong windRelatively Moderate
- TornadoRelatively Moderate
- DroughtRelatively Low
- EarthquakeRelatively Low
- HailRelatively Low
- WildfireRelatively Low
- LandslideVery Low
FEMA National Risk Index, December 2025
Questions about buying land in Onslow County
How much of Onslow County, NC is in a flood zone?
About 7.2% of Onslow County's area is in the 1%-annual-chance (100-year) floodplain used by FEMA's National Risk Index (December 2025), 49th highest of 100 counties in North Carolina. Another under 1% is exposed to coastal flooding. Whether a given parcel is in a flood zone depends on its exact location, so check the FEMA map at your pin.
How much does land cost per acre in Onslow County?
The 2022 Census of Agriculture put the average value of farm land and buildings in Onslow County at $6,189 an acre, 45th highest of 100 counties in North Carolina (the median North Carolina county was $5,848). It's a self-reported average across farms, so small homesites and recreational tracts often sell for more per acre.
Will a septic system work on land in Onslow County?
Often, but test first. USDA soil surveys rate 88% of Onslow County's mapped soils very limited for conventional septic absorption fields, usually because of wetness, slow permeability, shallow rock or flooding. A perc or soil test on the parcel decides what system the health department will permit.
Is there good farmland in Onslow County?
15% of Onslow County's mapped soils are prime farmland, 18% are prime only if drained, irrigated or protected from flooding, and 32% are farmland of statewide importance (USDA SSURGO). The 2022 Census of Agriculture counted 342 farms averaging 155 acres.
How often is Onslow County in drought?
Since 2021, at least half of the county was in severe drought or worse in 12% of weekly U.S. Drought Monitor maps, and in extreme drought in 0%. On 2026-10-27, 100% of the county was in moderate drought or worse.
Can I check a specific property in Onslow County?
Yes. Enter the address or drop a pin anywhere in Onslow County on the free check. It shows which checks return data at that exact point, and the full report costs $29: flood zone, slope, soils, wetlands, roads, power lines, wildfire and more, each with its source. It is a screen of public maps, not a survey, title search or perc test.
Check the parcel, not just the county
County numbers tell you what to look for. The free check looks at your exact point in Onslow County: flood zone, slope, soils, wetlands, roads, power and more. The full report is $29.
What these numbers can't tell you
- County shares describe Onslow County as a whole; a parcel can be entirely in or out of a flood zone, wetland or poor soil.
- It doesn't look at the whole parcel, its boundaries, title, easements, zoning or permits.
- It isn't a survey, appraisal, elevation certificate, soil or perc test, or Phase I environmental site assessment.
- It can't see local distribution power lines, driveways, legal access, wells or mineral rights.
- Maps lag behind the ground, and distances are straight-line, not driving distance.
Sources and vintages
- U.S. Census Bureau, 2024 Gazetteer Files: 2024 files
- U.S. Census Bureau, Vintage 2024 county population estimates: Vintage 2024 (July 1, 2024)
- U.S. Census Bureau, 2020 Census urban and rural classification: 2020 Census
- U.S. Census Bureau, 2024 county adjacency file: 2024
- FEMA National Risk Index: December 2025 release
- USDA NRCS Web Soil Survey (SSURGO): Soil Data Access, queried 2026-10-31
- USDA NASS, 2022 Census of Agriculture: 2022 Census of Agriculture (published 2024)
- U.S. Drought Monitor county statistics: weekly maps 2021-10-26 to 2026-10-27
- FEMA Flood Map Service Center: look up your own pin
- USFWS National Wetlands Inventory mapper: look up your own pin
Summarized per county by our build script on 2026-10-31. County figures cover the whole county; checks on the report are at your point.