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

Mercer County Disaster Risk

Mercer County, Ohio

FEMA Risk Rating

Very Low

National Percentile

32th

of 3,144 counties

State Rank

#73

of 88 (1 = highest risk)

Flood Risk

42th

percentile

Hazard Risk Breakdown

Flood

River, coastal, and surface flooding risk

Very Low

Higher than 42% of US counties

Wildfire

Wildland and wildland-urban interface fire risk

Very Low

Higher than 6% of US counties

Tornado

Tornado and severe thunderstorm risk

Relatively Low

Higher than 67% of US counties

Earthquake

Seismic activity and ground shaking risk

Relatively Low

Higher than 74% of US counties

Hurricane

Tropical cyclone and hurricane risk

Very Low

Higher than 39% of US counties

Risk Overview

About Natural Disaster Risk in Mercer County, Ohio

Mercer County's natural disaster risk

Mercer County scores 31.65 on the composite natural disaster risk scale, earning a Very Low rating—43% below Ohio's 55.03 state average. The county experiences substantially lower hazard exposure than most of its state peers across multiple disaster categories. Residents here enjoy some of Ohio's most favorable disaster risk conditions.

Among Ohio's safest counties

Mercer County ranks among Ohio's lowest-risk counties with its 31.65 composite score, well below the 55.03 state average. Only a handful of Ohio counties maintain lower overall risk profiles. This favorable positioning reflects geographic advantages and reduced exposure to the state's most common hazards.

Safer than most surrounding areas

Mercer County's 31.65 risk score outperforms nearby Marion County (61.10), Medina County (68.96), and Miami County (61.39). It ranks similarly to Madison County (24.90) and Monroe County (27.26) as one of northwest Ohio's safest communities. This clustering of low-risk counties reflects a regional advantage for disaster preparedness.

Earthquakes and tornadoes pose modest threat

Earthquake risk (73.82) and tornado risk (67.05) represent Mercer County's most significant hazards, though both remain manageable compared to higher-risk counties. Flood risk scores 42.08, while wildfire risk is minimal at 6.46. The county's overall low exposure means residents can focus on standard weather preparedness.

Basic homeowners coverage suffices

Standard homeowners insurance covering wind and hail damage adequately addresses Mercer County's modest tornado and severe weather exposure. While earthquake insurance is optional, the 73.82 score suggests discussing it with your agent. Flood insurance is a practical addition given the 42.08 flood risk, particularly if you live in a low-lying area.

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
    74th percentile
  2. #2
    TornadoPrepare
    67th percentile
  3. #3
    FloodPrepare
    42th percentile

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

Risk Advisory: Mercer County

Risk Verdict

Mercer County carries a low natural disaster risk burden, scoring at the 32th percentile under the FEMA National Risk Index. Being ranked at the 32th percentile nationally is an advantage for Mercer County — it means fewer statistically likely events, though basic readiness ensures households are covered when exceptions occur.

Hazard Breakdown

Earthquake risk is Mercer County's dominant natural hazard, ranked at the 74th percentile nationally under FEMA's National Risk Index. Tornado ranks second at the 67th percentile nationally. Additional tracked hazards include flood (42th percentile), hurricane (39th percentile), wildfire (6th percentile).

Preparedness Context

Mercer County's primary hazard, earthquake, ranks at the 74th percentile nationally. Unreinforced masonry structures carry the highest injury risk during seismic events; residents in older buildings should check with their municipality about available seismic retrofit programs. Tornado at the 67th percentile nationally is a separate hazard dimension for Mercer County that requires different protective strategies from earthquake preparedness. After a major earthquake, Mercer County residents should expect water service disruption for 24 to 72 or more hours. Storing a minimum of one gallon per person per day for three days — before any event — is the most direct preparedness action households can take.

Regional Context

Compared to the Ohio county average, Mercer County's composite score runs 23.4 points lower — a gap that reflects the county's relatively modest hazard profile within its state context.

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, OH?
Mercer County has a FEMA National Risk Index rating of Very Low, placing it in the 32th 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 (74th percentile), tornado (67th percentile), flooding (42th percentile), hurricane (39th percentile), wildfire (6th percentile). The highest-risk hazard is earthquake at the 74th 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 Ohio average?
Mercer County's composite risk percentile is 32th, compared to the Ohio 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 Ohio.
Is Mercer County at risk for earthquake?
Yes, Mercer County's earthquake risk is at the 74th percentile nationally. This is above the national median. For flooding specifically, Mercer County is at the 42th 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 32th percentile is below the Ohio 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 74th 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.