Is Sullivan County, TN in a flood zone?
FEMA's National Risk Index puts Sullivan County's flood hazard at the 81.6th percentile nationally — a middling flood hazard by national standards — driven by inland rivers and flash flooding rather than the coast — FEMA's model puts a flood event here at about 1.3 times a year. County-wide, not parcel-specific: FEMA's real flood-zone map is queried live, never shipped as a download.
Mandatory flood insurance compliance in Sullivan County
Homes with a federally backed mortgage inside Sullivan 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, 19.5% of them do — 188 active policies against 966 structures FEMA counts in that zone, leaving a real compliance gap. Across all residential structures in Sullivan County, not just the ones FEMA mandates, 0.4% carry an NFIP policy — most flood damage nationally happens outside the mapped high-risk zone, so that broader number matters too.
How Sullivan County compares nationally
Sullivan County sits at rank 604 of 3144 counties on FEMA's flood hazard scale (1 is worst) and rank 431 of 3144 by population (1 is biggest). About 162,703 people live in Sullivan County, Tennessee, spread over 413.545 square miles.
Checking a specific address in Sullivan County
266 of Sullivan County's 61,203 residential structures carry flood coverage of some kind, per FEMA's latest count — useful context, not a substitute for checking one parcel.
More on how this number was built
The methodology guide shows exactly which FEMA and Census tables feed Sullivan 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.