Pennsylvania coastal flooding risk
Philadelphia County has the highest coastal flooding risk in Pennsylvania, scoring 85.4 out of 100 — rated "Relatively High" by FEMA's National Risk Index.
| # | County | NRI score | Rating |
|---|---|---|---|
| 1 | Philadelphia County | 85.4 | Relatively High |
| 2 | Bucks County | 65 | Relatively Moderate |
| 3 | Delaware County | 63.6 | Relatively Moderate |
| 4 | Erie County | 36.4 | Very Low |
| 5 | Chester County | 0 | No Rating |
| 6 | Montgomery County | 0 | No Rating |
Source: FEMA National Risk Index v1.20.0, December 2025. Scores are 0–100 percentile rankings among all US counties. See the methodology page for definitions. Download the full CSV for all counties.
Coastal Flooding risk nationally:
Other hazard risks in Pennsylvania:
Frequently asked questions
What is the highest coastal flooding risk county in Pennsylvania?
Philadelphia County, PA has the highest coastal flooding risk in Pennsylvania, with a FEMA National Risk Index score of 85.4 out of 100 (rated "Relatively High").
What causes coastal flooding risk in Pennsylvania?
Coastal flooding scores cover storm surge, wave action, and tidal flooding along the Gulf, Atlantic, and Pacific coasts, and Great Lakes shoreline. Inland flooding is scored separately. Counties with "Not Applicable" ratings have no significant coastal exposure. Coastal flood events are reported at zone level in NOAA Storm Events and are not included in county-level counts.