Nassau County, FL flood risk explained
Flood hazard in Nassau County sits at the 75.8th national percentile, a middling flood hazard by national standards; driven by coastal storm surge rather than inland rivers — FEMA's model puts a surge event here at about 3.5 times a year. County-wide, not parcel-specific: FEMA's real flood-zone map is queried live, never shipped as a download.
Mandatory flood insurance compliance in Nassau County
60.7% of the homes FEMA requires to carry flood insurance in Nassau County — those inside the mapped Special Flood Hazard Area — actually have a policy in force: 2,013 policies against 3,317 mandated structures, which means a meaningful share of legally-required coverage simply isn't there. Looking beyond the mandated zone, 16.1% of all residential structures in Nassau County carry flood coverage voluntarily or otherwise — relevant because most NFIP claims nationally come from outside the mapped SFHA.
Nassau County against the rest of the country
Among the 3144 US counties FEMA scores for flood hazard, Nassau County ranks 795 — 1 being the highest hazard nationally — and 600 by population among all 3144 counties covered here, where 1 is the largest. About 104,376 people live in Nassau County, Florida, spread over 648.681 square miles.
What to do next if you own or are buying in Nassau County
Across all of Nassau County's 39,005 residential structures, 6,287 carry an NFIP policy today — a county-wide count that still can't tell you one address's own mapped zone.
Where Nassau County's figures come from
Every figure on this page traces to a named FEMA dataset, documented in the methodology guide. Nassau County's coastal exposure is covered in the coastal vs. inland flood risk guide, including how storm surge risk differs from river flooding.