How much flood risk does Jefferson County actually carry?
Jefferson County lands at the 99.1th percentile of FEMA's National Risk Index for flooding, "Relatively High" territory — well above the national norm for flood hazard — with the hazard driven by inland rivers and flash flooding rather than the coast — FEMA's model puts a flood event here at about 3.9 times a year. That's a county-wide figure, not a per-address one — FEMA's parcel maps are a live lookup, not a bulk file.
Jefferson County's flood-insurance compliance gap
52.8% of the homes FEMA requires to carry flood insurance in Jefferson County — those inside the mapped Special Flood Hazard Area — actually have a policy in force: 2,428 policies against 4,595 mandated structures, which means a meaningful share of legally-required coverage simply isn't there. Across all residential structures in Jefferson County, not just the ones FEMA mandates, 1.2% carry an NFIP policy — most flood damage nationally happens outside the mapped high-risk zone, so that broader number matters too.
Jefferson County against the rest of the country
Jefferson County sits at rank 34 of 3144 counties on FEMA's flood hazard scale (1 is worst) and rank 83 of 3144 by population (1 is biggest). Jefferson County, Kentucky covers 380.84 square miles and counts roughly 793,881 residents.
Your street may differ from Jefferson County's average
FEMA counts 243,583 residential structures in Jefferson County overall, 2,982 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.