St. Mary Parish, LA: flood risk, in FEMA's own numbers
On FEMA's National Risk Index, St. Mary Parish scores at the 93th 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 3.8 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.
Mandatory flood insurance compliance in St. Mary Parish
Out of 5,751 homes FEMA counts inside St. Mary Parish's mapped flood zone, 1,513 carry the flood policy federal law requires there — 26.3% compliance, short of full coverage. Looking beyond the mandated zone, 12.4% of all residential structures in St. Mary Parish carry flood coverage voluntarily or otherwise — relevant because most NFIP claims nationally come from outside the mapped SFHA.
St. Mary Parish against the rest of the country
Among the 3144 US counties FEMA scores for flood hazard, St. Mary Parish ranks 239 — 1 being the highest hazard nationally — and 1055 by population among all 3144 counties covered here, where 1 is the largest. St. Mary Parish, Louisiana is home to about 46,799 people across 558.528 square miles of land.
Checking a specific address in St. Mary Parish
FEMA counts 20,439 residential structures in St. Mary Parish overall, 2,543 of them carrying some form of NFIP coverage — but a lender or insurer cares about one parcel, not that county total.
Where St. Mary Parish's figures come from
Every figure on this page traces to a named FEMA dataset, documented in the methodology guide. St. Mary Parish's coastal exposure is covered in the coastal vs. inland flood risk guide, including how storm surge risk differs from river flooding.