Pennington County, SD: flood risk, in FEMA's own numbers
On FEMA's National Risk Index, Pennington County scores at the 75.6th percentile for flood hazard, rated "Relatively Moderate" — a middling flood hazard by national standards. The hazard here is driven by inland rivers and flash flooding rather than the coast — FEMA's model puts a flood event here at about 2.1 times a year. This describes the county, not any one street — FEMA only publishes exact parcel zones through a live map service.
Pennington County's flood-insurance compliance gap
15.6% of the homes FEMA requires to carry flood insurance in Pennington County — those inside the mapped Special Flood Hazard Area — actually have a policy in force: 195 policies against 1,251 mandated structures, which means a meaningful share of legally-required coverage simply isn't there. Looking beyond the mandated zone, 0.6% of all residential structures in Pennington County carry flood coverage voluntarily or otherwise — relevant because most NFIP claims nationally come from outside the mapped SFHA.
How Pennington County compares nationally
Among the 3144 US counties FEMA scores for flood hazard, Pennington County ranks 801 — 1 being the highest hazard nationally — and 548 by population among all 3144 counties covered here, where 1 is the largest. Pennington County, South Dakota covers 2,776.765 square miles and counts roughly 115,979 residents.
What to do next if you own or are buying in Pennington County
Across all of Pennington County's 40,123 residential structures, 253 carry an NFIP policy today — a county-wide count that still can't tell you one address's own mapped zone.
Where Pennington County's figures come from
Every figure on this page traces to a named FEMA dataset, documented in the methodology guide. If you're unsure why any of this insurance requirement exists at all, the SFHA explainer covers it from first principles.