Custer County, ID: flood risk, in FEMA's own numbers
On FEMA's National Risk Index, Custer County scores at the 57.3th percentile for flood hazard, rated "Relatively Low" — below the national norm for flood hazard. 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 once every 2 years. 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
FEMA hasn't published a residential structure count for Custer County's mapped flood zone, so a reliable mandatory-compliance percentage can't be computed here — see the data quality guide for why this gap exists for roughly a quarter of US counties. Looking beyond the mandated zone, 0.4% 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.
Custer County against the rest of the country
Among the 3144 US counties FEMA scores for flood hazard, Custer County ranks 1407 — 1 being the highest hazard nationally — and 2848 by population among all 3144 counties covered here, where 1 is the largest. Custer County, Idaho is home to about 4,597 people across 4,922.177 square miles of land.
What to do next if you own or are buying in Custer County
FEMA counts 4,224 residential structures in Custer County overall, 17 of them carrying some form of NFIP coverage — but a lender or insurer cares about one parcel, not that county total.
Where Custer County's figures come from
Every figure on this page traces to a named FEMA dataset, documented in the methodology guide. Custer County's compliance figure is one of the ones affected by FEMA's incomplete denominator data — the data quality guide explains what that means and how many counties it touches.