Brown County, IL flood risk explained
Flood hazard in Brown County sits at the 4.1th 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. County-wide, not parcel-specific: FEMA's real flood-zone map is queried live, never shipped as a download.
Mandatory flood insurance compliance in Brown County
Homes with a federally backed mortgage inside Brown County's mapped high-risk flood zone (the Special Flood Hazard Area, or SFHA) are legally required to carry an NFIP flood policy. In practice, 13.3% of them do — 2 active policies against 15 structures FEMA counts in that zone, leaving a real compliance gap. Looking beyond the mandated zone, 0.2% of all residential structures in Brown County carry flood coverage voluntarily or otherwise — relevant because most NFIP claims nationally come from outside the mapped SFHA.
Brown County against the rest of the country
Among the 3144 US counties FEMA scores for flood hazard, Brown County ranks 3020 — 1 being the highest hazard nationally — and 2713 by population among all 3144 counties covered here, where 1 is the largest. Brown County, Illinois is home to about 6,307 people across 305.727 square miles of land.
Checking a specific address in Brown County
FEMA counts 2,149 residential structures in Brown County overall, 4 of them carrying some form of NFIP coverage — but a lender or insurer cares about one parcel, not that county total.
Where Brown 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.