Is Franklin County, IL in a flood zone?
FEMA's National Risk Index puts Franklin County's flood hazard at the 65.7th percentile nationally — below the national norm for flood hazard — driven by inland rivers and flash flooding rather than the coast — FEMA's model puts a flood event here at about 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
Homes with a federally backed mortgage inside Franklin 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, 10% of them do — 34 active policies against 339 structures FEMA counts in that zone, leaving a real compliance gap. Across all residential structures in Franklin County, not just the ones FEMA mandates, 0.3% carry an NFIP policy — most flood damage nationally happens outside the mapped high-risk zone, so that broader number matters too.
How Franklin County compares nationally
Franklin County sits at rank 1126 of 3144 counties on FEMA's flood hazard scale (1 is worst) and rank 1261 of 3144 by population (1 is biggest). About 37,033 people live in Franklin County, Illinois, spread over 408.935 square miles.
Checking a specific address in Franklin County
Across all of Franklin County's 17,198 residential structures, 48 carry an NFIP policy today — a county-wide count that still can't tell you one address's own mapped zone.
More on how this number was built
The methodology guide shows exactly which FEMA and Census tables feed Franklin 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.