St. Martin Parish, LA: flood risk, in FEMA's own numbers
On FEMA's National Risk Index, St. Martin Parish scores at the 87th percentile for flood hazard, rated "Relatively High" — well above the national norm for flood hazard. The hazard here is driven by coastal storm surge rather than inland rivers — FEMA's model puts a surge event here at about 3.7 times a year. County-wide, not parcel-specific: FEMA's real flood-zone map is queried live, never shipped as a download.
Who actually carries the flood insurance FEMA requires
Homes with a federally backed mortgage inside St. Martin Parish's mapped high-risk flood zone (the Special Flood Hazard Area, or SFHA) are legally required to carry an NFIP flood policy. In practice, 24.8% of them do — 1,295 active policies against 5,221 structures FEMA counts in that zone, leaving a real compliance gap. Looking beyond the mandated zone, 9.9% of all residential structures in St. Martin Parish carry flood coverage voluntarily or otherwise — relevant because most NFIP claims nationally come from outside the mapped SFHA.
Where St. Martin Parish ranks
Among the 3144 US counties FEMA scores for flood hazard, St. Martin Parish ranks 430 — 1 being the highest hazard nationally — and 993 by population among all 3144 counties covered here, where 1 is the largest. About 51,218 people live in St. Martin Parish, Louisiana, spread over 737.549 square miles.
Your street may differ from St. Martin Parish's average
Across all of St. Martin Parish's 21,852 residential structures, 2,157 carry an NFIP policy today — a county-wide count that still can't tell you one address's own mapped zone.
Where St. Martin Parish's figures come from
Every figure on this page traces to a named FEMA dataset, documented in the methodology guide. St. Martin Parish's coastal exposure is covered in the coastal vs. inland flood risk guide, including how storm surge risk differs from river flooding.