How much flood risk does Knox County actually carry?
Knox County lands at the 92.8th percentile of FEMA's National Risk Index for flooding, "Relatively Moderate" territory — a middling flood hazard by national standards — with the hazard driven by inland rivers and flash flooding rather than the coast — FEMA's model puts a flood event here at about 2.2 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.
Who actually carries the flood insurance FEMA requires
Homes with a federally backed mortgage inside Knox 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, 41.4% of them do — 373 active policies against 900 structures FEMA counts in that zone, leaving a real compliance gap. Across all residential structures in Knox 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.
Knox County against the rest of the country
Knox County sits at rank 242 of 3144 counties on FEMA's flood hazard scale (1 is worst) and rank 147 of 3144 by population (1 is biggest). Knox County, Tennessee is home to about 506,748 people across 508.325 square miles of land.
Your street may differ from Knox County's average
FEMA counts 167,460 residential structures in Knox County overall, 772 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 Knox 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.