Is Montgomery County, MD in a flood zone?
FEMA's National Risk Index puts Montgomery County's flood hazard at the 93.7th 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 5.5 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.
Who actually carries the flood insurance FEMA requires
Homes with a federally backed mortgage inside Montgomery County's mapped high-risk flood zone (the Special Flood Hazard Area, or SFHA) are legally required to carry an NFIP flood policy. In practice, 51.1% of them do — 156 active policies against 305 structures FEMA counts in that zone, leaving a real compliance gap. Across all residential structures in Montgomery County, not just the ones FEMA mandates, 0.8% carry an NFIP policy — most flood damage nationally happens outside the mapped high-risk zone, so that broader number matters too.
How Montgomery County compares nationally
Montgomery County sits at rank 214 of 3144 counties on FEMA's flood hazard scale (1 is worst) and rank 44 of 3144 by population (1 is biggest). Montgomery County, Maryland covers 493.142 square miles and counts roughly 1,082,273 residents.
What to do next if you own or are buying in Montgomery County
Across all of Montgomery County's 257,826 residential structures, 2,029 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 Montgomery County's numbers. The guide to what the Special Flood Hazard Area actually means explains why the mandatory-insurance rule exists and who it applies to.