Is Hamilton County, IA in a flood zone?
FEMA's National Risk Index puts Hamilton County's flood hazard at the 41th 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 2.2 times a year. This describes the county, not any one street — FEMA only publishes exact parcel zones through a live map service.
Mandatory flood insurance compliance in Hamilton County
Out of 113 homes FEMA counts inside Hamilton County's mapped flood zone, 2 carry the flood policy federal law requires there — 1.8% compliance, short of full coverage. Across all residential structures in Hamilton County, not just the ones FEMA mandates, 0.1% carry an NFIP policy — most flood damage nationally happens outside the mapped high-risk zone, so that broader number matters too.
How Hamilton County compares nationally
Hamilton County sits at rank 1915 of 3144 counties on FEMA's flood hazard scale (1 is worst) and rank 2099 of 3144 by population (1 is biggest). Hamilton County, Iowa is home to about 14,856 people across 576.731 square miles of land.
Checking a specific address in Hamilton County
Across all of Hamilton County's 11,019 residential structures, 6 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 Hamilton 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.