How much flood risk does Madison County actually carry?
Madison County lands at the 57.8th percentile of FEMA's National Risk Index for flooding, "Relatively Low" territory — below the national norm for flood hazard — 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. This describes the county, not any one street — FEMA only publishes exact parcel zones through a live map service.
Mandatory flood insurance compliance in Madison County
Madison 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 Madison County, not just the ones FEMA mandates, 0.2% carry an NFIP policy — most flood damage nationally happens outside the mapped high-risk zone, so that broader number matters too.
How Madison County compares nationally
Madison County sits at rank 1389 of 3144 counties on FEMA's flood hazard scale (1 is worst) and rank 942 of 3144 by population (1 is biggest). About 55,549 people live in Madison County, Idaho, spread over 469.267 square miles.
Checking a specific address in Madison County
FEMA counts 9,051 residential structures in Madison County overall, 21 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 Madison County's numbers. See the data quality guide for why Madison County, like hundreds of other counties, doesn't get a clean compliance percentage.