Is Jefferson Parish, LA in a flood zone?
FEMA's National Risk Index puts Jefferson Parish's flood hazard at the 96th percentile nationally — among the highest flood hazard in the country — split between inland river flooding (about 2 times a year) and coastal storm surge (about 2.8 times a year). County-wide, not parcel-specific: FEMA's real flood-zone map is queried live, never shipped as a download.
Who actually carries the flood insurance FEMA requires
The raw NFIP numbers for Jefferson Parish 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 Jefferson Parish, not just the ones FEMA mandates, 64.9% carry an NFIP policy — most flood damage nationally happens outside the mapped high-risk zone, so that broader number matters too.
Where Jefferson Parish ranks
Jefferson Parish sits at rank 137 of 3144 counties on FEMA's flood hazard scale (1 is worst) and rank 177 of 3144 by population (1 is biggest). Jefferson Parish, Louisiana covers 300.864 square miles and counts roughly 427,253 residents.
What to do next if you own or are buying in Jefferson Parish
Across all of Jefferson Parish's 116,441 residential structures, 75,564 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 Jefferson Parish's numbers. See the data quality guide for why Jefferson Parish, like hundreds of other counties, doesn't get a clean compliance percentage.