How much flood risk does Sanborn County actually carry?
Sanborn County lands at the 6.2th percentile of FEMA's National Risk Index for flooding, "Very Low" territory — among the lowest flood hazard in the country — 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. County-wide, not parcel-specific: FEMA's real flood-zone map is queried live, never shipped as a download.
Who actually carries the flood insurance FEMA requires
3.6% of the homes FEMA requires to carry flood insurance in Sanborn County — those inside the mapped Special Flood Hazard Area — actually have a policy in force: 1 policies against 28 mandated structures, which means a meaningful share of legally-required coverage simply isn't there. Across all residential structures in Sanborn County, not just the ones FEMA mandates, 0.1% carry an NFIP policy — most flood damage nationally happens outside the mapped high-risk zone, so that broader number matters too.
Where Sanborn County ranks
Sanborn County sits at rank 2960 of 3144 counties on FEMA's flood hazard scale (1 is worst) and rank 3008 of 3144 by population (1 is biggest). Sanborn County, South Dakota is home to about 2,392 people across 569.242 square miles of land.
What to do next if you own or are buying in Sanborn County
FEMA counts 2,080 residential structures in Sanborn County overall, 1 of them carrying some form of NFIP coverage — but a lender or insurer cares about one parcel, not that county total.
More on how this number was built
The methodology guide shows exactly which FEMA and Census tables feed Sanborn 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.