riskbycounty
FEMA NRI 1.19.0Updated Nov 2023 · Coverage 2014–2023Methodology

Johnson County Disaster Risk

Johnson County, Illinois

FEMA Risk Rating

Relatively Low

National Percentile

51th

of 3,144 counties

State Rank

#58

of 102 (1 = highest risk)

Flood Risk

38th

percentile

Hazard Risk Breakdown

Flood

River, coastal, and surface flooding risk

Very Low

Higher than 38% of US counties

Wildfire

Wildland and wildland-urban interface fire risk

Very Low

Higher than 11% of US counties

Tornado

Tornado and severe thunderstorm risk

Relatively Low

Higher than 56% of US counties

Earthquake

Seismic activity and ground shaking risk

Moderate

Higher than 91% of US counties

Hurricane

Tropical cyclone and hurricane risk

Very Low

Higher than 38% of US counties

Risk Overview

About Natural Disaster Risk in Johnson County, Illinois

Johnson County's risk falls below state average

Johnson County's composite risk score of 51.08 sits comfortably below Illinois's state average of 54.46, earning a relatively low risk rating. The county's balanced hazard profile avoids extreme exposure to any single disaster type, making it among the safer areas statewide.

Lower-risk county in Illinois

With a score of 51.08 versus the state average of 54.46, Johnson County ranks in the safer half of Illinois counties. The county's earthquake risk of 91.00 stands out as notably high, but other hazards remain moderate to low.

Safest among southern Illinois counties

Johnson County's 51.08 score is substantially lower than Jefferson County (77.23) to the north and comparable to Jo Daviess County (51.30) in the far north. This positions Johnson as one of the safer options in its region.

Earthquakes pose the main threat here

Johnson County's earthquake risk of 91.00 is its dominant natural hazard, though tornado risk of 56.04 and hurricane risk of 38.09 remain moderate. Flood and wildfire risks are relatively subdued at 37.88 and 11.26 respectively.

Earthquake insurance is the priority

Johnson County residents should prioritize earthquake insurance given the county's 91.00 seismic risk score—among the highest statewide. Standard homeowners insurance is typically sufficient for tornado and flood exposure, but earthquake coverage is a prudent investment for this location.

Source: FEMA National Risk Index · Narrative reviewed by Evan Brooks, Data Editor

Preparedness Guide

What to Prepare for in Johnson County

Top Hazards by Exposure

  1. #1
    EarthquakePrepare
    91th percentile
  2. #2
    TornadoPrepare
    56th percentile
  3. #3
    HurricanePrepare
    38th percentile

Source: FEMA National Risk Index v1.19.0 · Percentiles are national (3,144 counties)

Local Resources

Risk Advisory: Johnson County

Risk Verdict

Johnson County has a below-average natural disaster risk profile, scoring at the 51th percentile nationally under FEMA's National Risk Index. Households in Johnson County benefit from knowing which individual hazard types — flood, wildfire, tornado, or hurricane — are the primary contributors.

Hazard Breakdown

Earthquake risk is Johnson County's dominant natural hazard, ranked at the 91th percentile nationally under FEMA's National Risk Index. Tornado ranks second at the 56th percentile nationally. Additional tracked hazards include hurricane (38th percentile), flood (38th percentile), wildfire (11th percentile).

Preparedness Context

Earthquake risk is Johnson County's leading natural hazard, ranked at the 91th percentile nationally. Securing tall furniture, water heaters, and bookcases to walls with anti-tip hardware is among the simplest and most effective life-safety measures households can take. Tornado at the 56th percentile nationally is a separate hazard dimension for Johnson County that requires different protective strategies from earthquake preparedness. Johnson County residents should locate the main gas shutoff valve and keep an appropriate wrench nearby — gas leaks cause a significant share of earthquake-related injuries and fires, and the shutoff step is safe to take immediately after shaking stops.

Regional Context

At just 3.4 composite points from the Illinois average, Johnson County's natural disaster risk is closely in line with its in-state peers.

Is your household prepared for Johnson County's hazards?

Review FEMA's county-specific preparedness checklists and emergency planning guides.

FEMA Ready Guide →

Frequently Asked Questions

What is the natural disaster risk in Johnson County, IL?
Johnson County has a FEMA National Risk Index rating of Relatively Low, placing it in the 51th percentile nationally out of 3,144 counties. This composite score reflects the county's overall exposure to natural hazards including floods, wildfires, tornadoes, earthquakes, and hurricanes, weighted by expected annual loss and social vulnerability.
What types of natural hazards affect Johnson County?
Johnson County is evaluated for five major natural hazard types: earthquake (91th percentile), tornado (56th percentile), hurricane (38th percentile), flooding (38th percentile), wildfire (11th percentile). The highest-risk hazard is earthquake at the 91th percentile nationally. These scores are derived from FEMA's National Risk Index, which analyzes expected annual loss, social vulnerability, and community resilience for each hazard type.
How does Johnson County risk compare to the Illinois average?
Johnson County's composite risk percentile is 51th, compared to the Illinois state average of 55th percentile. The state's overall risk rating is Relatively Low. This means Johnson County faces lower natural disaster risk than the typical county in Illinois.
Is Johnson County at risk for earthquake?
Yes, Johnson County's earthquake risk is at the 91th percentile nationally. This places it in the top quartile for this hazard type. For flooding specifically, Johnson County is at the 38th percentile.
How is natural disaster risk measured?
FEMA's National Risk Index (NRI) calculates risk scores for 18 natural hazard types across all U.S. counties and census tracts. The composite score combines Expected Annual Loss (estimated dollar losses from each hazard), Social Vulnerability (demographic factors affecting disaster impact), and Community Resilience (ability to recover). Percentile scores rank each county against all 3,144 U.S. counties, and risk ratings range from Very Low to Very High.
Is Johnson County a safe place to live?
Johnson County's composite risk score of 51th percentile is below the Illinois state average of 55th percentile, indicating relatively lower exposure to natural hazards. However, no county is completely risk-free. The primary hazard type is earthquake at the 91th percentile. Residents should still maintain emergency preparedness plans and appropriate insurance coverage.

Counties with Similar Risk

Jo Daviess County

Illinois

+0.2

Relatively Low

51th percentile

Shelby County

Illinois

+0.7

Relatively Low

52th percentile

Lawrence County

Illinois

-1.8

Relatively Low

49th percentile

By Evan Brooks, Data EditorUpdated Reviewed by Evan Brooks, Data Editor

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.

Explore more data for Johnson County

Property TaxCost of LivingCrime RateIncomeHealthSchoolsWater QualityWeatherCounty Score