Is Jefferson County, OK in a flood zone?
FEMA's National Risk Index puts Jefferson County's flood hazard at the 14.2th percentile nationally — among the lowest flood hazard in the country — driven by inland rivers and flash flooding rather than the coast — FEMA's model puts a flood event here at about once every 1 years. 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
Jefferson County is one of the counties where FEMA's own denominator for mandated flood-zone structures is missing, so no compliance rate is shown rather than a guessed one — the data quality guide covers how common this is. Across all residential structures in Jefferson County, not just the ones FEMA mandates, 0.1% carry an NFIP policy — most flood damage nationally happens outside the mapped high-risk zone, so that broader number matters too.
Where Jefferson County ranks
Jefferson County sits at rank 2730 of 3144 counties on FEMA's flood hazard scale (1 is worst) and rank 2790 of 3144 by population (1 is biggest). About 5,374 people live in Jefferson County, Oklahoma, spread over 758.956 square miles.
Your street may differ from Jefferson County's average
2 of Jefferson County's 3,571 residential structures carry flood coverage of some kind, per FEMA's latest count — useful context, not a substitute for checking one parcel.
More on how this number was built
The methodology guide shows exactly which FEMA and Census tables feed Jefferson County's numbers. See the data quality guide for why Jefferson County, like hundreds of other counties, doesn't get a clean compliance percentage.