Onslow County, NC flood risk explained
Flood hazard in Onslow County sits at the 81th national percentile, a middling flood hazard by national standards; split between inland river flooding (about 1.5 times a year) and coastal storm surge (about 3.3 times a year). That's a county-wide figure, not a per-address one — FEMA's parcel maps are a live lookup, not a bulk file.
Onslow County's flood-insurance compliance gap
Homes with a federally backed mortgage inside Onslow County's mapped high-risk flood zone (the Special Flood Hazard Area, or SFHA) are legally required to carry an NFIP flood policy. In practice, 73.4% of them do — 2,562 active policies against 3,491 structures FEMA counts in that zone, leaving a real compliance gap. Looking beyond the mandated zone, 6.3% of all residential structures in Onslow County carry flood coverage voluntarily or otherwise — relevant because most NFIP claims nationally come from outside the mapped SFHA.
Where Onslow County ranks
Among the 3144 US counties FEMA scores for flood hazard, Onslow County ranks 622 — 1 being the highest hazard nationally — and 332 by population among all 3144 counties covered here, where 1 is the largest. About 212,954 people live in Onslow County, North Carolina, spread over 762.085 square miles.
What to do next if you own or are buying in Onslow County
Across all of Onslow County's 69,807 residential structures, 4,401 carry an NFIP policy today — a county-wide count that still can't tell you one address's own mapped zone.
Where Onslow County's figures come from
Every figure on this page traces to a named FEMA dataset, documented in the methodology guide. Onslow County's coastal exposure is covered in the coastal vs. inland flood risk guide, including how storm surge risk differs from river flooding.