How much flood risk does Minnehaha County actually carry?
Minnehaha County lands at the 85.5th percentile of FEMA's National Risk Index for flooding, "Relatively Moderate" territory — a middling flood hazard by national standards — with the hazard driven by inland rivers and flash flooding rather than the coast — FEMA's model puts a flood event here at about 4.5 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 Minnehaha County
19.1% of the homes FEMA requires to carry flood insurance in Minnehaha County — those inside the mapped Special Flood Hazard Area — actually have a policy in force: 119 policies against 624 mandated structures, which means a meaningful share of legally-required coverage simply isn't there. Across all residential structures in Minnehaha 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.
Where Minnehaha County ranks
Minnehaha County sits at rank 479 of 3144 counties on FEMA's flood hazard scale (1 is worst) and rank 342 of 3144 by population (1 is biggest). About 208,639 people live in Minnehaha County, South Dakota, spread over 806.86 square miles.
Checking a specific address in Minnehaha County
Across all of Minnehaha County's 62,351 residential structures, 214 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 Minnehaha 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.