How much flood risk does Grand Isle County actually carry?
Grand Isle County lands at the 12.8th percentile of FEMA's National Risk Index for flooding, "Very Low" territory — among the lowest flood hazard in the country — with the hazard driven by inland rivers and flash flooding rather than the coast — FEMA's model puts a flood event here at about once every 2 years. 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 Grand Isle County
Grand Isle County is one of the counties where FEMA's own denominator for mandated flood-zone structures is missing, so no compliance rate is shown rather than a guessed one — the data quality guide covers how common this is. Across all residential structures in Grand Isle County, not just the ones FEMA mandates, 1.5% carry an NFIP policy — most flood damage nationally happens outside the mapped high-risk zone, so that broader number matters too.
How Grand Isle County compares nationally
Grand Isle County sits at rank 2767 of 3144 counties on FEMA's flood hazard scale (1 is worst) and rank 2615 of 3144 by population (1 is biggest). Grand Isle County, Vermont covers 81.771 square miles and counts roughly 7,528 residents.
Your street may differ from Grand Isle County's average
FEMA counts 5,193 residential structures in Grand Isle County overall, 78 of them carrying some form of NFIP coverage — but a lender or insurer cares about one parcel, not that county total.
More on how this number was built
The methodology guide shows exactly which FEMA and Census tables feed Grand Isle County's numbers. See the data quality guide for why Grand Isle County, like hundreds of other counties, doesn't get a clean compliance percentage.