Delaware landslide risk
New Castle County has the highest landslide risk in Delaware, scoring 76.6 out of 100 — rated "Relatively Low" by FEMA's National Risk Index.
| # | County | NRI score | Rating |
NOAA events 2016–2026 |
|---|---|---|---|---|
| 1 | New Castle County | 76.6 | Relatively Low | 0 |
| 2 | Sussex County | 50.6 | Very Low | 0 |
| 3 | Kent County | 30.2 | Very Low | 0 |
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.
Landslide risk nationally:
Other hazard risks in Delaware:
Frequently asked questions
What is the highest landslide risk county in Delaware?
New Castle County, DE has the highest landslide risk in Delaware, with a FEMA National Risk Index score of 76.6 out of 100 (rated "Relatively Low").
What causes landslide risk in Delaware?
Landslide risk covers expected losses from hillslope failures, rockfalls, and debris flows triggered by heavy rainfall, snowmelt, wildfire, or earthquakes. High scores concentrate in the Pacific Northwest, California coastal ranges, Appalachians, and Rocky Mountain foothills, where steep terrain combines with intense precipitation or seismic activity.