Big Horn County, MT: flood risk, in FEMA's own numbers
On FEMA's National Risk Index, Big Horn County scores at the 55.1th 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 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.
Big Horn County's flood-insurance compliance gap
FEMA hasn't published a residential structure count for Big Horn 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, 0.1% of all residential structures in Big Horn County carry flood coverage voluntarily or otherwise — relevant because most NFIP claims nationally come from outside the mapped SFHA.
Big Horn County against the rest of the country
Among the 3144 US counties FEMA scores for flood hazard, Big Horn County ranks 1478 — 1 being the highest hazard nationally — and 2233 by population among all 3144 counties covered here, where 1 is the largest. Big Horn County, Montana covers 4,997.778 square miles and counts roughly 12,796 residents.
Your street may differ from Big Horn County's average
6 of Big Horn County's 4,915 residential structures carry flood coverage of some kind, per FEMA's latest count — useful context, not a substitute for checking one parcel.
Where Big Horn County's figures come from
Every figure on this page traces to a named FEMA dataset, documented in the methodology guide. Big Horn 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.