How much flood risk does Plymouth County actually carry?
Plymouth County lands at the 94.4th percentile of FEMA's National Risk Index for flooding, "Very High" territory — among the highest flood hazard in the country — with the hazard split between inland river flooding (about 2.3 times a year) and coastal storm surge (about 7.1 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
Out of 11,912 homes FEMA counts inside Plymouth County's mapped flood zone, 6,185 carry the flood policy federal law requires there — 51.9% compliance, short of full coverage. Across all residential structures in Plymouth County, not just the ones FEMA mandates, 4.3% carry an NFIP policy — most flood damage nationally happens outside the mapped high-risk zone, so that broader number matters too.
Plymouth County against the rest of the country
Plymouth County sits at rank 191 of 3144 counties on FEMA's flood hazard scale (1 is worst) and rank 133 of 3144 by population (1 is biggest). Plymouth County, Massachusetts is home to about 542,090 people across 658.521 square miles of land.
Your street may differ from Plymouth County's average
Across all of Plymouth County's 165,654 residential structures, 7,128 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 Plymouth County's numbers. Because storm surge plays a real role here, the guide to coastal vs. inland flood hazard is worth reading alongside this page.