Jefferson County Disaster Risk
Jefferson County, Illinois
FEMA Risk Rating
Relatively Low
National Percentile
77th
of 3,144 counties
State Rank
#27
of 102 (1 = highest risk)
Flood Risk
59th
percentile
Hazard Risk Breakdown
Flood
River, coastal, and surface flooding risk
Relatively Low
Higher than 59% of US counties
Wildfire
Wildland and wildland-urban interface fire risk
Very Low
Higher than 10% of US counties
Tornado
Tornado and severe thunderstorm risk
Relatively Low
Higher than 79% of US counties
Earthquake
Seismic activity and ground shaking risk
Relatively High
Higher than 96% of US counties
Hurricane
Tropical cyclone and hurricane risk
Very Low
Higher than 39% of US counties
Risk Overview
About Natural Disaster Risk in Jefferson County, Illinois
Jefferson County faces above-average disaster risk
With a composite risk score of 77.23, Jefferson County ranks as relatively low risk but significantly exceeds Illinois's state average of 54.46. This places the county in the higher-risk category nationally, driven primarily by severe earthquake and tornado exposure.
Higher-risk county in Illinois rankings
Jefferson County's 77.23 score ranks it among the riskier counties statewide, well above the state average of 54.46. The county's earthquake risk of 95.83 is particularly notable, putting it in the highest tier for seismic activity in the state.
Riskier than most nearby counties
Jefferson County's composite score of 77.23 exceeds neighboring Johnson County (51.08) and Knox County (57.16) significantly. Only Kane County to the north approaches similar risk levels, making Jefferson an outlier in the region for earthquake and tornado exposure.
Earthquakes and tornadoes dominate here
Earthquake risk reaches 95.83—nearly double the state average—while tornado risk stands at a substantial 79.07. Flooding poses moderate concern at 58.97, meaning residents face compound hazard exposure across multiple disaster types.
Prioritize earthquake and storm coverage now
Standard homeowners policies rarely cover earthquakes or tornadoes; Jefferson County residents should actively purchase separate earthquake insurance and ensure comprehensive storm coverage. With combined earthquake and tornado scores exceeding 170, reinforced foundation anchoring and a safe room for severe weather are practical investments.
Source: FEMA National Risk Index · Narrative reviewed by Evan Brooks, Data Editor
Preparedness Guide
What to Prepare for in Jefferson County
Top Hazards by Exposure
Source: FEMA National Risk Index v1.19.0 · Percentiles are national (3,144 counties)
Risk Advisory: Jefferson County
Risk Verdict
With a national percentile rank of 77th, Jefferson County faces below-average hazard exposure relative to U.S. counties as a whole. Proactive preparedness — not reactive response — is key to managing life in one of the country's higher-risk counties; Jefferson County residents should plan accordingly.
Hazard Breakdown
Earthquake risk is Jefferson County's dominant natural hazard, ranked at the 96th percentile nationally under FEMA's National Risk Index. Tornado ranks second at the 79th percentile nationally. Additional tracked hazards include flood (59th percentile), hurricane (39th percentile), wildfire (10th percentile).
Preparedness Context
At the 96th percentile nationally for earthquake exposure, Jefferson County households benefit from practicing Drop, Cover, and Hold On — the protocol that minimizes injury during shaking. Getting under a sturdy table or desk and holding on until shaking stops is the key action. Tornado at the 79th percentile nationally is a separate hazard dimension for Jefferson County that requires different protective strategies from earthquake preparedness. Building age matters for earthquake risk in Jefferson County: structures built before local seismic code adoption are statistically more vulnerable. Contacting the local building department about retrofit programs can reveal whether your structure qualifies for mitigation assistance.
Regional Context
At 22.8 points above the Illinois state average, Jefferson County carries meaningfully higher natural disaster exposure than a typical Illinois county.
Is your household prepared for Jefferson County's hazards?
Review FEMA's county-specific preparedness checklists and emergency planning guides.
Frequently Asked Questions
What is the natural disaster risk in Jefferson County, IL?
What types of natural hazards affect Jefferson County?
How does Jefferson County risk compare to the Illinois average?
Is Jefferson County at risk for earthquake?
How is natural disaster risk measured?
Why is Jefferson County higher risk than average?
Data Source
Risk data sourced from the FEMA National Risk Index (NRI). Risk scores are relative rankings (0–100) across all US counties — not absolute risk measures. Higher scores indicate higher relative risk compared to other counties.
Disclaimer: This data is informational only. It is not financial, insurance, or legal advice. Always consult a qualified professional before making insurance or real estate decisions.