Greene County, IL flood risk explained
Flood hazard in Greene County sits at the 13.2th national percentile, among the lowest flood hazard in the country; 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 Greene County
Out of 126 homes FEMA counts inside Greene County's mapped flood zone, 9 carry the flood policy federal law requires there — 7.1% compliance, short of full coverage. Looking beyond the mandated zone, 0.2% of all residential structures in Greene County carry flood coverage voluntarily or otherwise — relevant because most NFIP claims nationally come from outside the mapped SFHA.
Where Greene County ranks
Among the 3144 US counties FEMA scores for flood hazard, Greene County ranks 2755 — 1 being the highest hazard nationally — and 2321 by population among all 3144 counties covered here, where 1 is the largest. Greene County, Illinois is home to about 11,417 people across 543.144 square miles of land.
What to do next if you own or are buying in Greene County
FEMA counts 4,977 residential structures in Greene County overall, 10 of them carrying some form of NFIP coverage — but a lender or insurer cares about one parcel, not that county total.
Where Greene County's figures come from
Every figure on this page traces to a named FEMA dataset, documented in the methodology guide. If you're unsure why any of this insurance requirement exists at all, the SFHA explainer covers it from first principles.