Rockingham County, NH: flood risk, in FEMA's own numbers
On FEMA's National Risk Index, Rockingham County scores at the 92.8th percentile for flood hazard, rated "Relatively High" — well above the national norm for flood hazard. The hazard here is split between inland river flooding (about 1.2 times a year) and coastal storm surge (about 8 times a year). This describes the county, not any one street — FEMA only publishes exact parcel zones through a live map service.
Mandatory flood insurance compliance in Rockingham County
37.5% of the homes FEMA requires to carry flood insurance in Rockingham County — those inside the mapped Special Flood Hazard Area — actually have a policy in force: 1,480 policies against 3,948 mandated structures, which means a meaningful share of legally-required coverage simply isn't there. Looking beyond the mandated zone, 2.2% of all residential structures in Rockingham County carry flood coverage voluntarily or otherwise — relevant because most NFIP claims nationally come from outside the mapped SFHA.
Rockingham County against the rest of the country
Among the 3144 US counties FEMA scores for flood hazard, Rockingham County ranks 244 — 1 being the highest hazard nationally — and 230 by population among all 3144 counties covered here, where 1 is the largest. Rockingham County, New Hampshire covers 695.554 square miles and counts roughly 322,433 residents.
Your street may differ from Rockingham County's average
Across all of Rockingham County's 92,454 residential structures, 2,047 carry an NFIP policy today — a county-wide count that still can't tell you one address's own mapped zone.
Where Rockingham County's figures come from
Every figure on this page traces to a named FEMA dataset, documented in the methodology guide. Rockingham County's coastal exposure is covered in the coastal vs. inland flood risk guide, including how storm surge risk differs from river flooding.