Yankton County, SD flood risk explained
Flood hazard in Yankton County sits at the 57.3th national percentile, 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 2.3 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.
Yankton County's flood-insurance compliance gap
Homes with a federally backed mortgage inside Yankton County's mapped high-risk flood zone (the Special Flood Hazard Area, or SFHA) are legally required to carry an NFIP flood policy. In practice, 19.2% of them do — 52 active policies against 271 structures FEMA counts in that zone, leaving a real compliance gap. Looking beyond the mandated zone, 0.9% of all residential structures in Yankton County carry flood coverage voluntarily or otherwise — relevant because most NFIP claims nationally come from outside the mapped SFHA.
Yankton County against the rest of the country
Among the 3144 US counties FEMA scores for flood hazard, Yankton County ranks 1406 — 1 being the highest hazard nationally — and 1664 by population among all 3144 counties covered here, where 1 is the largest. Yankton County, South Dakota is home to about 23,509 people across 521.189 square miles of land.
What to do next if you own or are buying in Yankton County
Across all of Yankton County's 7,499 residential structures, 69 carry an NFIP policy today — a county-wide count that still can't tell you one address's own mapped zone.
Where Yankton 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.