Is Union County, OH in a flood zone?
FEMA's National Risk Index puts Union County's flood hazard at the 52.7th 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 1.5 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.
Mandatory flood insurance compliance in Union County
Homes with a federally backed mortgage inside Union 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, 15.5% of them do — 26 active policies against 168 structures FEMA counts in that zone, leaving a real compliance gap. Across all residential structures in Union 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 Union County compares nationally
Union County sits at rank 1548 of 3144 counties on FEMA's flood hazard scale (1 is worst) and rank 771 of 3144 by population (1 is biggest). Union County, Ohio is home to about 71,721 people across 431.713 square miles of land.
Checking a specific address in Union County
Across all of Union County's 22,008 residential structures, 58 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 Union 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.