Is Boone County, IL in a flood zone?
FEMA's National Risk Index puts Boone County's flood hazard at the 63.9th percentile nationally — below the national norm for flood hazard — driven by inland rivers and flash flooding rather than the coast — FEMA's model puts a flood event here at about once every 1 years. County-wide, not parcel-specific: FEMA's real flood-zone map is queried live, never shipped as a download.
Boone County's flood-insurance compliance gap
Out of 175 homes FEMA counts inside Boone County's mapped flood zone, 45 carry the flood policy federal law requires there — 25.7% compliance, short of full coverage. Across all residential structures in Boone County, not just the ones FEMA mandates, 0.3% carry an NFIP policy — most flood damage nationally happens outside the mapped high-risk zone, so that broader number matters too.
Where Boone County ranks
Boone County sits at rank 1184 of 3144 counties on FEMA's flood hazard scale (1 is worst) and rank 971 of 3144 by population (1 is biggest). Boone County, Illinois covers 280.749 square miles and counts roughly 53,313 residents.
What to do next if you own or are buying in Boone County
FEMA counts 19,078 residential structures in Boone County overall, 62 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 Boone County's numbers. The guide to what the Special Flood Hazard Area actually means explains why the mandatory-insurance rule exists and who it applies to.