Jefferson County, MT: flood risk, in FEMA's own numbers
On FEMA's National Risk Index, Jefferson County scores at the 29.4th percentile for flood hazard, rated "Very Low" — among the lowest flood hazard in the country. 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 6 years. County-wide, not parcel-specific: FEMA's real flood-zone map is queried live, never shipped as a download.
Jefferson County's flood-insurance compliance gap
FEMA hasn't published a residential structure count for Jefferson 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, 0.3% of all residential structures in Jefferson County carry flood coverage voluntarily or otherwise — relevant because most NFIP claims nationally come from outside the mapped SFHA.
Jefferson County against the rest of the country
Among the 3144 US counties FEMA scores for flood hazard, Jefferson County ranks 2275 — 1 being the highest hazard nationally — and 2205 by population among all 3144 counties covered here, where 1 is the largest. Jefferson County, Montana is home to about 13,304 people across 1,656.997 square miles of land.
Checking a specific address in Jefferson County
22 of Jefferson County's 6,728 residential structures carry flood coverage of some kind, per FEMA's latest count — useful context, not a substitute for checking one parcel.
Where Jefferson County's figures come from
Every figure on this page traces to a named FEMA dataset, documented in the methodology guide. Jefferson 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.