Hamilton County, IL: flood risk, in FEMA's own numbers
On FEMA's National Risk Index, Hamilton County scores at the 12.5th percentile for flood hazard, rated "Very Low" — among the lowest flood hazard in the country. The hazard here is driven by inland rivers and flash flooding rather than the coast — FEMA's model puts a flood event here at about 1.4 times a year. This describes the county, not any one street — FEMA only publishes exact parcel zones through a live map service.
Who actually carries the flood insurance FEMA requires
FEMA hasn't published a residential structure count for Hamilton County's mapped flood zone, so a reliable mandatory-compliance percentage can't be computed here — see the data quality guide for why this gap exists for roughly a quarter of US counties. Looking beyond the mandated zone, 0% of all residential structures in Hamilton County carry flood coverage voluntarily or otherwise — relevant because most NFIP claims nationally come from outside the mapped SFHA.
How Hamilton County compares nationally
Among the 3144 US counties FEMA scores for flood hazard, Hamilton County ranks 2774 — 1 being the highest hazard nationally — and 2588 by population among all 3144 counties covered here, where 1 is the largest. Hamilton County, Illinois is home to about 7,818 people across 434.653 square miles of land.
What to do next if you own or are buying in Hamilton County
FEMA counts 2,808 residential structures in Hamilton County overall, 0 of them carrying some form of NFIP coverage — but a lender or insurer cares about one parcel, not that county total.
Where Hamilton County's figures come from
Every figure on this page traces to a named FEMA dataset, documented in the methodology guide. Hamilton County's compliance figure is one of the ones affected by FEMA's incomplete denominator data — the data quality guide explains what that means and how many counties it touches.