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

Mercer County Disaster Risk

Mercer County, Illinois

FEMA Risk Rating

Very Low

National Percentile

9th

of 3,144 counties

State Rank

#97

of 102 (1 = highest risk)

Flood Risk

9th

percentile

Hazard Risk Breakdown

Flood

River, coastal, and surface flooding risk

Very Low

Higher than 9% of US counties

Wildfire

Wildland and wildland-urban interface fire risk

Very Low

Higher than 1% of US counties

Tornado

Tornado and severe thunderstorm risk

Very Low

Higher than 23% of US counties

Earthquake

Seismic activity and ground shaking risk

Very Low

Higher than 25% of US counties

Hurricane

Tropical cyclone and hurricane risk

Very Low

Higher than 11% of US counties

Risk Overview

About Natural Disaster Risk in Mercer County, Illinois

Mercer County ranks among nation's safest

Mercer County's composite risk score of 8.78 places it well below the national average, earning a very low risk rating. This county experiences substantially less exposure to major natural disasters than most U.S. counties.

Illinois's lowest-risk county

With a composite score less than one-sixth of Illinois's 54.46 average, Mercer County is the safest county in the state by this measure. No Illinois county ranks notably lower for overall natural disaster risk.

Significantly safer than surrounding counties

Mercer County's risk score of 8.78 is dramatically lower than neighboring Menard County (28.69), Monroe County (41.86), and Morgan County (71.12). Residents here enjoy exceptional protection from natural hazards compared to the broader central Illinois region.

Earthquakes the primary concern

Earthquake risk (24.68) and tornado risk (22.52) represent Mercer County's top hazards, both well below state levels. Flood (9.16), wildfire (1.08), and hurricane (11.31) risks are all minimal in this county.

Focus on standard homeowner protection

A solid homeowners insurance policy covering tornado and wind damage provides adequate protection for Mercer County residents. While earthquake risk remains low, adding earthquake coverage offers inexpensive peace of mind in this exceptionally safe region.

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

Preparedness Guide

What to Prepare for in Mercer County

Top Hazards by Exposure

  1. #1
    EarthquakePrepare
    25th percentile
  2. #2
    TornadoPrepare
    23th percentile
  3. #3
    HurricanePrepare
    11th percentile

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

Risk Advisory: Mercer County

Risk Verdict

At the 9th percentile nationally, Mercer County experiences relatively limited natural hazard pressure compared to most of the country. The 9th percentile national ranking is one lens; Mercer County residents also benefit from reviewing which specific hazard types drive the county's composite score and preparing accordingly.

Hazard Breakdown

Earthquake risk is Mercer County's dominant natural hazard, ranked at the 25th percentile nationally under FEMA's National Risk Index. Tornado ranks second at the 23th percentile nationally. Additional tracked hazards include hurricane (11th percentile), flood (9th percentile), wildfire (1th percentile).

Preparedness Context

Mercer County ranks at the 25th percentile nationally for earthquake risk. Unlike most natural hazards, earthquakes provide no advance warning; preparedness here means structural adjustments and a practiced response, not alert monitoring. The county's tornado risk at the 23th percentile nationally is a seasonal consideration alongside the year-round earthquake threat, requiring awareness of both hazard types. For earthquake preparedness, Mercer County's county emergency management office often maintains a list of community water supply points, Red Cross shelter locations, and post-quake assistance programs — useful resources to identify before an event occurs.

Regional Context

A composite score 45.7 points below the Illinois state average puts Mercer County in a better-than-typical position relative to neighboring counties.

Is your household prepared for Mercer 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 Mercer County, IL?
Mercer County has a FEMA National Risk Index rating of Very Low, placing it in the 9th 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 Mercer County?
Mercer County is evaluated for five major natural hazard types: earthquake (25th percentile), tornado (23th percentile), hurricane (11th percentile), flooding (9th percentile), wildfire (1th percentile). The highest-risk hazard is earthquake at the 25th 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 Mercer County risk compare to the Illinois average?
Mercer County's composite risk percentile is 9th, compared to the Illinois state average of 55th percentile. The state's overall risk rating is Relatively Low. This means Mercer County faces lower natural disaster risk than the typical county in Illinois.
Is Mercer County at risk for earthquake?
Yes, Mercer County's earthquake risk is at the 25th percentile nationally. This is below the national median, indicating relatively lower exposure. For flooding specifically, Mercer County is at the 9th 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 Mercer County a safe place to live?
Mercer County's composite risk score of 9th 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 25th percentile. Residents should still maintain emergency preparedness plans and appropriate insurance coverage.
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.