Out of 67 counties with earthquake data, these are the counties with the highest seismic risk.
| Statistic | Value |
|---|---|
| Counties ranked | 67 |
| Avg earthquake risk (top 100) | 0.9/50 |
Top 67 Counties
| Rank | County | State | Risk Score | Rating | Expected Annual Loss |
|---|---|---|---|---|---|
| 1 | Oglala Lakota | South Dakota | 2.8/50 | Very Low | $7K |
| 2 | Shannon | South Dakota | 2.3/50 | Very Low | $7K |
| 3 | Fall River | South Dakota | 2.2/50 | Very Low | $11K |
| 4 | Charles Mix | South Dakota | 2.1/50 | Very Low | $11K |
| 5 | Pennington | South Dakota | 2/50 | Very Low | $59K |
| 6 | Minnehaha | South Dakota | 1.8/50 | Very Low | $49K |
| 7 | Beadle,Kingsbury | South Dakota | 1.8/50 | Very Low | $19K |
| 8 | Beadle | South Dakota | 1.8/50 | Very Low | $19K |
| 9 | Bennett | South Dakota | 1.6/50 | Very Low | $3K |
| 10 | Lawrence | South Dakota | 1.5/50 | Very Low | $13K |
| 11 | Mellette | South Dakota | 1.5/50 | Very Low | $3K |
| 12 | Davison | South Dakota | 1.4/50 | Very Low | $17K |
| 13 | Hutchinson | South Dakota | 1.4/50 | Very Low | $6K |
| 14 | Yankton | South Dakota | 1.3/50 | Very Low | $16K |
| 15 | Brown | South Dakota | 1.3/50 | Very Low | $15K |
| 16 | Tripp | South Dakota | 1.2/50 | Very Low | $5K |
| 17 | Jerauld | South Dakota | 1.2/50 | Very Low | $4K |
| 18 | Lyman | South Dakota | 1.1/50 | Very Low | $5K |
| 19 | Douglas | South Dakota | 1.1/50 | Very Low | $5K |
| 20 | Brule | South Dakota | 1.1/50 | Very Low | $4K |
| 21 | Bon Homme | South Dakota | 1/50 | Very Low | $11K |
| 22 | Aurora | South Dakota | 1/50 | Very Low | $6K |
| 23 | Custer | South Dakota | 1/50 | Very Low | $6K |
| 24 | Gregory | South Dakota | 1/50 | Very Low | $3K |
| 25 | Roberts | South Dakota | 1/50 | Very Low | $2K |
| 26 | Spink | South Dakota | 0.9/50 | Very Low | $15K |
| 27 | Codington | South Dakota | 0.9/50 | Very Low | $7K |
| 28 | Lake | South Dakota | 0.9/50 | Very Low | $5K |
| 29 | Hand | South Dakota | 0.9/50 | Very Low | $4K |
| 30 | Jackson | South Dakota | 0.9/50 | Very Low | $2K |
| 31 | Clark | South Dakota | 0.8/50 | Very Low | $19K |
| 32 | Clay | South Dakota | 0.8/50 | Very Low | $6K |
| 33 | Hughes | South Dakota | 0.8/50 | Very Low | $6K |
| 34 | Turner | South Dakota | 0.8/50 | Very Low | $4K |
| 35 | Day | South Dakota | 0.8/50 | Very Low | $2K |
| 36 | Brookings | South Dakota | 0.7/50 | Very Low | $9K |
| 37 | Meade | South Dakota | 0.7/50 | Very Low | $8K |
| 38 | Butte | South Dakota | 0.7/50 | Very Low | $8K |
| 39 | Hyde | South Dakota | 0.7/50 | Very Low | $6K |
| 40 | Sanborn | South Dakota | 0.7/50 | Very Low | $3K |
| 41 | McCook | South Dakota | 0.7/50 | Very Low | $3K |
| 42 | Kingsbury | South Dakota | 0.7/50 | Very Low | $3K |
| 43 | Potter | South Dakota | 0.7/50 | Very Low | $2K |
| 44 | Union | South Dakota | 0.6/50 | Very Low | $11K |
| 45 | Moody | South Dakota | 0.6/50 | Very Low | $5K |
| 46 | Miner | South Dakota | 0.6/50 | Very Low | $5K |
| 47 | Faulk | South Dakota | 0.6/50 | Very Low | $4K |
| 48 | Hamlin | South Dakota | 0.6/50 | Very Low | $3K |
| 49 | McPherson | South Dakota | 0.6/50 | Very Low | $574 |
| 50 | Lincoln | South Dakota | 0.5/50 | Very Low | $12K |
| 51 | Hanson | South Dakota | 0.5/50 | Very Low | $2K |
| 52 | Haakon | South Dakota | 0.5/50 | Very Low | $2K |
| 53 | Edmunds | South Dakota | 0.5/50 | Very Low | $2K |
| 54 | Walworth | South Dakota | 0.5/50 | Very Low | $636 |
| 55 | Dewey | South Dakota | 0.5/50 | Very Low | $636 |
| 56 | Ziebach | South Dakota | 0.5/50 | Very Low | $302 |
| 57 | Grant | South Dakota | 0.4/50 | Very Low | $2K |
| 58 | Stanley | South Dakota | 0.4/50 | Very Low | $1K |
| 59 | Brookings,Deuel | South Dakota | 0.4/50 | Very Low | $1K |
| 60 | Deuel | South Dakota | 0.4/50 | Very Low | $1K |
| 61 | Marshall | South Dakota | 0.4/50 | Very Low | $639 |
| 62 | Corson | South Dakota | 0.4/50 | Very Low | $294 |
| 63 | Sully | South Dakota | 0.3/50 | Very Low | $6K |
| 64 | Jones | South Dakota | 0.3/50 | Very Low | $572 |
| 65 | Perkins | South Dakota | 0.3/50 | Very Low | $358 |
| 66 | Campbell | South Dakota | 0.3/50 | Very Low | $294 |
| 67 | Harding | South Dakota | 0.1/50 | Very Low | $206 |
* = New Madrid Seismic Zone
Methodology
County rankings for South Dakota based on average FEMA earthquake risk score.
Data sources: FEMA National Risk Index, USGS Earthquake Hazards Program. Last updated: 2026-06-04.
Frequently Asked Questions
How is earthquake risk calculated?
Earthquake risk scores (0-50) are from the FEMA National Risk Index, which combines seismic hazard exposure, community vulnerability, and expected losses. Higher scores indicate greater earthquake risk to people and property.
What is the New Madrid Seismic Zone?
The New Madrid Seismic Zone spans parts of Missouri, Tennessee, Arkansas, Kentucky, Illinois, Indiana, and Mississippi. The 1811-1812 New Madrid earthquakes (estimated M7.5-7.9) were among the strongest in U.S. history. This region remains seismically active, and most buildings were not designed to withstand major earthquakes.
Does earthquake risk affect home insurance?
Standard homeowners insurance does not cover earthquake damage. Separate earthquake insurance is required, and premiums vary significantly based on location, construction type, and proximity to fault lines.