Is Multnomah County, OR in a flood zone?
FEMA's National Risk Index puts Multnomah County's flood hazard at the 95.5th percentile nationally — well above 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 3 years. 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 Multnomah County
The raw NFIP numbers for Multnomah County would imply over 100% of mandated homes carry a policy, which just means FEMA's structure-count denominator for this county is wrong, not that compliance is unusually good. This is flagged rather than clipped to look normal — details in the data quality guide. Across all residential structures in Multnomah County, not just the ones FEMA mandates, 0.5% carry an NFIP policy — most flood damage nationally happens outside the mapped high-risk zone, so that broader number matters too.
How Multnomah County compares nationally
Multnomah County sits at rank 152 of 3144 counties on FEMA's flood hazard scale (1 is worst) and rank 82 of 3144 by population (1 is biggest). About 795,897 people live in Multnomah County, Oregon, spread over 431.012 square miles.
Your street may differ from Multnomah County's average
Across all of Multnomah County's 239,735 residential structures, 1,087 carry an NFIP policy today — a county-wide count that still can't tell you one address's own mapped zone.
More on how this number was built
The methodology guide shows exactly which FEMA and Census tables feed Multnomah County's numbers. See the data quality guide for why Multnomah County, like hundreds of other counties, doesn't get a clean compliance percentage.