Is Lemhi County, ID in a flood zone?
FEMA's National Risk Index puts Lemhi County's flood hazard at the 59.8th percentile nationally — below the national norm for flood hazard — 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. This describes the county, not any one street — FEMA only publishes exact parcel zones through a live map service.
Lemhi County's flood-insurance compliance gap
Lemhi County is one of the counties where FEMA's own denominator for mandated flood-zone structures is missing, so no compliance rate is shown rather than a guessed one — the data quality guide covers how common this is. Across all residential structures in Lemhi County, not just the ones FEMA mandates, 0.6% carry an NFIP policy — most flood damage nationally happens outside the mapped high-risk zone, so that broader number matters too.
Lemhi County against the rest of the country
Lemhi County sits at rank 1324 of 3144 counties on FEMA's flood hazard scale (1 is worst) and rank 2547 of 3144 by population (1 is biggest). About 8,397 people live in Lemhi County, Idaho, spread over 4,563.704 square miles.
What to do next if you own or are buying in Lemhi County
31 of Lemhi County's 5,304 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 Lemhi County's numbers. See the data quality guide for why Lemhi County, like hundreds of other counties, doesn't get a clean compliance percentage.