Is Jefferson County, KS in a flood zone?
FEMA's National Risk Index puts Jefferson County's flood hazard at the 32.6th percentile nationally — 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 1.8 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
Out of 256 homes FEMA counts inside Jefferson County's mapped flood zone, 35 carry the flood policy federal law requires there — 13.7% compliance, short of full coverage. Across all residential structures in Jefferson County, not just the ones FEMA mandates, 0.5% carry an NFIP policy — most flood damage nationally happens outside the mapped high-risk zone, so that broader number matters too.
Where Jefferson County ranks
Jefferson County sits at rank 2178 of 3144 counties on FEMA's flood hazard scale (1 is worst) and rank 1915 of 3144 by population (1 is biggest). About 18,332 people live in Jefferson County, Kansas, spread over 532.626 square miles.
What to do next if you own or are buying in Jefferson County
FEMA counts 8,933 residential structures in Jefferson County overall, 48 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 Jefferson 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.