Custer County, SD flood risk explained
Flood hazard in Custer County sits at the 19.3th national percentile, among the lowest flood hazard in the country; driven by inland rivers and flash flooding rather than the coast — FEMA's model puts a flood event here at about 1.2 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 Custer County
12.6% of the homes FEMA requires to carry flood insurance in Custer County — those inside the mapped Special Flood Hazard Area — actually have a policy in force: 41 policies against 325 mandated structures, which means a meaningful share of legally-required coverage simply isn't there. Looking beyond the mandated zone, 0.8% of all residential structures in Custer County carry flood coverage voluntarily or otherwise — relevant because most NFIP claims nationally come from outside the mapped SFHA.
How Custer County compares nationally
Among the 3144 US counties FEMA scores for flood hazard, Custer County ranks 2578 — 1 being the highest hazard nationally — and 2465 by population among all 3144 counties covered here, where 1 is the largest. Custer County, South Dakota covers 1,556.943 square miles and counts roughly 9,330 residents.
Checking a specific address in Custer County
44 of Custer County's 5,843 residential structures carry flood coverage of some kind, per FEMA's latest count — useful context, not a substitute for checking one parcel.
Where Custer 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.