Linn County, IA: flood risk, in FEMA's own numbers
On FEMA's National Risk Index, Linn County scores at the 86.7th percentile for flood hazard, rated "Relatively Moderate" — a middling flood hazard by national standards. 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 2.2 times a year. County-wide, not parcel-specific: FEMA's real flood-zone map is queried live, never shipped as a download.
Mandatory flood insurance compliance in Linn County
23.8% of the homes FEMA requires to carry flood insurance in Linn County — those inside the mapped Special Flood Hazard Area — actually have a policy in force: 252 policies against 1,061 mandated structures, which means a meaningful share of legally-required coverage simply isn't there. Looking beyond the mandated zone, 0.7% of all residential structures in Linn County carry flood coverage voluntarily or otherwise — relevant because most NFIP claims nationally come from outside the mapped SFHA.
Linn County against the rest of the country
Among the 3144 US counties FEMA scores for flood hazard, Linn County ranks 438 — 1 being the highest hazard nationally — and 312 by population among all 3144 counties covered here, where 1 is the largest. Linn County, Iowa covers 717.013 square miles and counts roughly 231,762 residents.
Your street may differ from Linn County's average
FEMA counts 90,749 residential structures in Linn County overall, 655 of them carrying some form of NFIP coverage — but a lender or insurer cares about one parcel, not that county total.
Where Linn County's figures come from
Every figure on this page traces to a named FEMA dataset, documented in the methodology guide. If you're unsure why any of this insurance requirement exists at all, the SFHA explainer covers it from first principles.