Is Winnebago County, WI in a flood zone?
FEMA's National Risk Index puts Winnebago County's flood hazard at the 89.3th 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 once every 2 years. 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 Winnebago 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, 20.5% of them do — 289 active policies against 1,411 structures FEMA counts in that zone, leaving a real compliance gap. Across all residential structures in Winnebago County, not just the ones FEMA mandates, 0.8% carry an NFIP policy — most flood damage nationally happens outside the mapped high-risk zone, so that broader number matters too.
Where Winnebago County ranks
Winnebago County sits at rank 354 of 3144 counties on FEMA's flood hazard scale (1 is worst) and rank 402 of 3144 by population (1 is biggest). About 173,307 people live in Winnebago County, Wisconsin, spread over 434.697 square miles.
Your street may differ from Winnebago County's average
FEMA counts 50,649 residential structures in Winnebago County overall, 413 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 Winnebago 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.