Honolulu County, HI: flood risk, in FEMA's own numbers
On FEMA's National Risk Index, Honolulu County scores at the 99.3th percentile for flood hazard, rated "Very High" — among the highest flood hazard in the country. The hazard here is driven by inland rivers and flash flooding rather than the coast — FEMA's model puts a flood event here at about 5.9 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.
Honolulu County's flood-insurance compliance gap
Homes with a federally backed mortgage inside Honolulu 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, 54% of them do — 4,490 active policies against 8,317 structures FEMA counts in that zone, leaving a real compliance gap. Looking beyond the mandated zone, 4.1% of all residential structures in Honolulu County carry flood coverage voluntarily or otherwise — relevant because most NFIP claims nationally come from outside the mapped SFHA.
Where Honolulu County ranks
Among the 3144 US counties FEMA scores for flood hazard, Honolulu County ranks 26 — 1 being the highest hazard nationally — and 51 by population among all 3144 counties covered here, where 1 is the largest. About 998,747 people live in Honolulu County, Hawaii, spread over 600.791 square miles.
Checking a specific address in Honolulu County
FEMA counts 169,009 residential structures in Honolulu County overall, 6,934 of them carrying some form of NFIP coverage — but a lender or insurer cares about one parcel, not that county total.
Where Honolulu County's figures come from
Every figure on this page traces to a named FEMA dataset, documented in the methodology guide. If you're unsure why any of this insurance requirement exists at all, the SFHA explainer covers it from first principles.