How much flood risk does Lake County actually carry?
Lake County lands at the 34.1th 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 once every 1 years. That's a county-wide figure, not a per-address one — FEMA's parcel maps are a live lookup, not a bulk file.
Who actually carries the flood insurance FEMA requires
27.8% of the homes FEMA requires to carry flood insurance in Lake County — those inside the mapped Special Flood Hazard Area — actually have a policy in force: 79 policies against 284 mandated structures, which means a meaningful share of legally-required coverage simply isn't there. Across all residential structures in Lake County, not just the ones FEMA mandates, 2.1% carry an NFIP policy — most flood damage nationally happens outside the mapped high-risk zone, so that broader number matters too.
Where Lake County ranks
Lake County sits at rank 2133 of 3144 counties on FEMA's flood hazard scale (1 is worst) and rank 2344 of 3144 by population (1 is biggest). Lake County, South Dakota is home to about 11,006 people across 562.905 square miles of land.
What to do next if you own or are buying in Lake County
139 of Lake County's 6,780 residential structures carry flood coverage of some kind, per FEMA's latest count — useful context, not a substitute for checking one parcel.
More on how this number was built
The methodology guide shows exactly which FEMA and Census tables feed Lake 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.