Some counties in America face natural disaster risk that far exceeds the national average. Using FEMA National Risk Index data, we identified the 25 counties with the highest composite risk scores — places where floods, wildfires, tornadoes, earthquakes, and hurricanes create overlapping hazard exposure.
These counties are not necessarily the most dangerous places to live on any given day. But over time, the cumulative risk of natural disasters translates into higher insurance costs, greater emergency preparedness needs, and more frequent disruptions to daily life.
The 25 Highest-Risk Counties in America
Los Angeles County, California tops the list with a composite risk score of 100. The following counties face the greatest overall natural disaster risk:
| Rank | County | State | Risk Score | Rating | Flood | Wildfire | Tornado | Hurricane |
|---|---|---|---|---|---|---|---|---|
| 1 | Los Angeles County, California | CA | 100 | Very High | 100 | 99.9364 | 97.6781 | 0 |
| 2 | Cook County, Illinois | IL | 99.9682 | Very High | 99.9364 | 55.7888 | 99.9682 | 48.8945 |
| 3 | Harris County, Texas | TX | 99.9364 | Very High | 99.9682 | 85.4326 | 100 | 100 |
| 4 | Riverside County, California | CA | 99.9046 | Very High | 99.9046 | 99.9682 | 86.7048 | 11.9733 |
| 5 | Maricopa County, Arizona | AZ | 99.8728 | Very High | 99.8728 | 99.6183 | 84.0013 | 26.5749 |
| 6 | San Bernardino County, California | CA | 99.841 | Very High | 99.841 | 99.9046 | 78.7532 | 0 |
| 7 | Orange County, California | CA | 99.8092 | Very High | 99.8092 | 99.8092 | 83.715 | 0 |
| 8 | Alameda County, California | CA | 99.7774 | Very High | 99.6819 | 97.7099 | 65.8079 | N/A |
| 9 | Santa Clara County, California | CA | 99.7455 | Very High | 99.7774 | 97.3919 | 55.7888 | N/A |
| 10 | San Diego County, California | CA | 99.7137 | Very High | 99.7455 | 100 | 64.4084 | 8.302 |
| 11 | King County, Washington | WA | 99.6819 | Very High | 99.4593 | 79.4529 | 73.1552 | N/A |
| 12 | Dallas County, Texas | TX | 99.6501 | Very High | 99.5547 | 80.2799 | 99.841 | 73.5503 |
| 13 | Miami-Dade County, Florida | FL | 99.6183 | Very High | 99.7137 | 96.8511 | 98.7277 | 99.9583 |
| 14 | Philadelphia County, Pennsylvania | PA | 99.5865 | Very High | 99.5865 | 28.6896 | 98.6641 | 94.2845 |
| 15 | Clark County, Nevada | NV | 99.5547 | Very High | 99.6183 | 99.1412 | 9.2239 | 0 |
| 16 | San Francisco County, California | CA | 99.5229 | Very High | 98.6005 | 28.6578 | 34.8601 | N/A |
| 17 | Contra Costa County, California | CA | 99.4911 | Very High | 99.4911 | 97.5827 | 49.8728 | N/A |
| 18 | Broward County, Florida | FL | 99.4593 | Relatively High | 99.4275 | 97.0102 | 96.2786 | 99.8331 |
| 19 | Bexar County, Texas | TX | 99.4275 | Relatively High | 99.6501 | 92.3664 | 99.9046 | 83.5211 |
| 20 | Ventura County, California | CA | 99.3957 | Relatively High | 99.2684 | 99.7774 | 42.43 | 0 |
| 21 | Shelby County, Tennessee | TN | 99.3639 | Relatively High | 98.6641 | 71.056 | 99.7774 | 67.1256 |
| 22 | St. Louis County, Missouri | MO | 99.3321 | Relatively High | 99.0776 | 61.7048 | 98.0598 | 45.098 |
| 23 | Fresno County, California | CA | 99.3003 | Relatively High | 98.6959 | 98.4415 | 57.1247 | N/A |
| 24 | Kings County, New York | NY | 99.2684 | Relatively High | 99.3639 | 38.5496 | 94.1794 | 97.4134 |
| 25 | San Mateo County, California | CA | 99.2366 | Relatively High | 98.4415 | 92.0165 | 30.6298 | N/A |
Where the Highest-Risk Counties Are Located
The highest-risk counties cluster in specific regions. California (12 counties), Texas (3 counties), Florida (2 counties), Illinois (1 counties), Arizona (1 counties) lead the rankings. Coastal counties in the Gulf and Atlantic states dominate due to hurricane and flood exposure, while California counties face compounded wildfire and earthquake risk.
Methodology
Composite risk scores come from the FEMA National Risk Index (2020), combining natural hazard exposure, expected annual loss, social vulnerability, and community resilience. Individual hazard scores are percentile ranks on a 0-100 scale. Counties are ranked by composite risk score in descending order.
Data source: FEMA National Risk Index (NRI). Risk scores use percentile-rank methodology on a 0-100 scale. All figures are relative rankings and do not represent absolute predictions of natural disaster occurrence.