Marion County, IN: flood risk, in FEMA's own numbers
On FEMA's National Risk Index, Marion County scores at the 98.3th percentile for flood hazard, rated "Relatively High" — well above 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 2.9 times a year. That's a county-wide figure, not a per-address one — FEMA's parcel maps are a live lookup, not a bulk file.
Mandatory flood insurance compliance in Marion County
16% of the homes FEMA requires to carry flood insurance in Marion County — those inside the mapped Special Flood Hazard Area — actually have a policy in force: 1,612 policies against 10,075 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 Marion County carry flood coverage voluntarily or otherwise — relevant because most NFIP claims nationally come from outside the mapped SFHA.
Where Marion County ranks
Among the 3144 US counties FEMA scores for flood hazard, Marion County ranks 61 — 1 being the highest hazard nationally — and 54 by population among all 3144 counties covered here, where 1 is the largest. Marion County, Indiana covers 395.996 square miles and counts roughly 981,628 residents.
Your street may differ from Marion County's average
2,066 of Marion County's 306,743 residential structures carry flood coverage of some kind, per FEMA's latest count — useful context, not a substitute for checking one parcel.
Where Marion 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.