How much flood risk does Marshall County actually carry?
Marshall County lands at the 63.1th percentile of FEMA's National Risk Index for flooding, "Relatively Low" territory — below the national norm for flood hazard — with the hazard driven by inland rivers and flash flooding rather than the coast — FEMA's model puts a flood event here at about 2.4 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 Marshall County
3.8% of the homes FEMA requires to carry flood insurance in Marshall County — those inside the mapped Special Flood Hazard Area — actually have a policy in force: 18 policies against 470 mandated structures, which means a meaningful share of legally-required coverage simply isn't there. Across all residential structures in Marshall County, not just the ones FEMA mandates, 0.2% carry an NFIP policy — most flood damage nationally happens outside the mapped high-risk zone, so that broader number matters too.
Where Marshall County ranks
Marshall County sits at rank 1211 of 3144 counties on FEMA's flood hazard scale (1 is worst) and rank 1183 of 3144 by population (1 is biggest). Marshall County, Iowa covers 572.503 square miles and counts roughly 40,392 residents.
What to do next if you own or are buying in Marshall County
27 of Marshall County's 17,985 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 Marshall 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.