FEMA Records
15
Below median
Illinois · FEMA + NOAA + National Risk Index
Mercer County, IL
15 FEMA disaster declarations (1965-2020), with a FEMA National Risk Index rating of Very Low. Most common hazard: Flood.
- 15
- FEMA declarations
- 11
- Major disasters
- 9
- NRI risk · Very Low
- Flood
- Top hazard
The verdict
Two federal records point in the busier direction for Mercer County. Its 15 FEMA declarations are 17% above the Illinois county mean and exceed the count for 23% of the 3,266 counties in this registry. Separately, FEMA's National Risk Index places it safer than 9%, based on modeled expected annual loss, social vulnerability, and community resilience.
- Safer than 9%
- of U.S. counties for FEMA National Risk Index score
- Very Low
- FEMA National Risk Index rating
- 15
- FEMA declarations vs 21 national county avg
- 61
- NFIP flood insurance claims filed
FEMA's National Risk Index and its declaration registry are separate measures. This county's registry includes Major Disaster (DR) and Emergency (EM) records; an EM authorizes a narrower set of federal assistance than a DR.
How does Mercer County compare?
Mercer County vs. all counties in this dataset
FEMA disaster declarations, all-time
15 23rd percentile higher than 23% of 3,266 counties
Each bar is a band; taller bars hold more counties. The dashed line + filled bar mark this entry. Hover or tap any bar for its full count, share, and where it sits relative to this entry.
Source FEMA Disaster Declarations Summaries v2 · 2026-08-03
Mercer County's FEMA Risk Index score
FEMA National Risk Index composite score vs. the Illinois county average
Which hazard drives modeled loss here?
FEMA's modeled annual dollar loss for Mercer County is led by Riverine Flooding (about $2.0M Expected Annual Loss, Historical Loss Ratio Relatively High), while Drought carries the highest National Risk Index rating (Relatively Moderate). EAL and risk score use different inputs; they need not agree.
Source: FEMA National Risk Index (December 2025 release) - Expected Annual Loss vs composite risk rating by hazard.
What does Mercer County's hazard record show?
Reading the federal records together
The NFIP claims register shows a middle-volume loss record here: 61 paid claims, totaling $1.4M. PlainHazard uses 50-499 claims for this descriptive band; FEMA does not publish it as a safety or coverage category. The $22.2K average describes payments on recorded claims only, leaving uninsured damage and properties without a claim outside the measure.
The declaration register points in the busier direction. Mercer County's 15 federal records stand 17% above the Illinois county mean of 12.9. That comparison describes how often federal action was recorded, including any Major Disaster, Emergency, and Fire Management entries shown on this page; it does not convert the count into future probability.
Declaration frequency
The FEMA register is busy by both local and national comparisons. It contains 15 entries for Mercer County, including 11 Major Disaster records, 17% above the Illinois county mean. Across the 55-year span, that works out to 0.3 declarations a year. Flood leads the file with 7 entries. Declaration type records the federal action taken, not every assistance program approved.
FEMA National Risk Index
FEMA's National Risk Index places this county in the low end of the national distribution, composite score 8.8/100 (Very Low). Expected Annual Loss is rated Very Low (roughly $6.9M in annualized losses). Two modifiers shape how that exposure becomes real-world harm here: social vulnerability (Very Low) and community resilience (Very High). Among the 18 modeled hazards, Drought carries the county's highest rating, a mid-range Relatively Moderate. FEMA's modeled frequency puts that hazard at 8.2 modeled event-days per year here, based on 217 historical events on record.
59 /100
Historical Activity Index
High historical activity
Mercer County, IL · PlainHazard-derived composite from federal records
This 0–100 index is an explicit PlainHazard composite from FEMA declaration history only on the county surface (this DB has no county-level NOAA damage row) . It is not FEMA's National Risk Index, not a forecast, and not a safety, insurance, or preparedness rating. Open the calculator · Methodology
FEMA Declarations (1953–present) Moderate
11/30
15 OpenFEMA declarations, full ingest window (0.7x national county average)
County Disaster Density High
15/25
15 declarations (1.2x state county average of 13)
Major Disaster Share High
18/25
11 of 15 declarations are major disasters (73%)
Hazard Diversity Very High
15/20
6 different disaster types declared in Mercer County
Historical Declaration Activity
Activity Band
High
vs. Illinois Avg
+17%
State avg: 12.9
vs. National Avg
-28%
National avg: 20.7
Avg Per Year
0.3
Over 55 years
FEMA NRI 8-hazard radar - Mercer County
How to read this radar
Each axis: NRI risk rating (Very Low-Very High) on a 0-100 scale. Rounder = broad exposure; spiky = one or two hazards dominate.
Major Disaster share
73%
Major-heavy
NRI risk score
9
Very Low
Source: FEMA National Risk Index Per-county per-hazard ratings, December 2025 release
How often does each hazard strike Mercer County?
FEMA's National Risk Index models a historical event count and an annualized frequency for each hazard type. Most hazards are expressed as modeled occurrences per year; FEMA expresses drought and heat-wave frequency as event-days per year. These modeled frequencies are not forecasts.
| Hazard | NRI Risk Rating | Recurrence |
|---|---|---|
| Drought | Relatively Moderate | 8.2 modeled event-days per year |
| Landslide | Relatively Low | roughly once every 4 years |
| Ice Storm | Relatively Moderate | roughly once every 1 years |
| Strong Wind | Relatively Moderate | an average of 6.2 times per year |
| Lightning | Relatively Moderate | an average of 45 times per year |
| Heat Wave | Relatively Low | 8.2 modeled event-days per year |
| Cold Wave | Relatively Low | an average of 5.4 times per year |
| Hail | Very Low | an average of 4.2 times per year |
| Winter Weather | Relatively Low | an average of 14 times per year |
| Earthquake | Very Low | roughly once every 855 years |
| Tornado | Very Low | roughly once every 2 years |
| Hurricane | Very Low | roughly once every 100 years |
| Riverine Flooding | Very Low | an average of 1.6 times per year |
| Wildfire | Very Low | roughly once every 3,362 years |
Source: FEMA National Risk Index Modeled annualized frequency; drought and heat wave use event-days/year, December 2025 release
Disaster Types
Flood 7
Snowstorm 3
Biological 2
Severe Storm 1
Hurricane 1
Tornado 1
What Flood declarations mean here
Flood is the most frequent declaration type on Mercer County's record, 47% of its declarations. Federal flood declarations cover two mechanisms that behave very differently: riverine flooding, which builds over days as a watershed drains and is usually forecast well in advance, and flash flooding, which can arrive in under an hour from rainfall that fell somewhere upstream.
Flood is also the one hazard class where a second federal dataset exists for the same events. The National Flood Insurance Program records what was actually paid on insured losses, so it measures a narrower thing than the declaration count: uninsured damage, and flooding outside mapped special flood hazard areas, never enters it. Reading the two together is more informative than either alone.
Declaration counts describe past federal action. They are a record of what was declared, not a forecast of future hazard probability.
Declaration Types
What DR / EM / FM mean
FEMA categorizes declarations as Major Disasters (DR), Emergencies (EM), or Fire Management Assistance (FM).
Major Disaster - 11 73.3%
of all 15 declarations
Emergency - 4 26.7%
of all 15 declarations
FEMA Declarations Timeline
| Year | Declarations | |
|---|---|---|
| 2020 | 2 | |
| 2019 | 1 | |
| 2013 | 1 | |
| 2011 | 1 | |
| 2008 | 1 | |
| 2005 | 1 | |
| 2001 | 1 | |
| 1999 | 1 | |
| 1993 | 1 | |
| 1979 | 1 | |
| 1974 | 1 | |
| 1973 | 1 | |
| 1969 | 1 | |
| 1965 | 1 | |
Disaster Declarations
How the 15 FEMA declarations break into federal action codes (DR / EM / FM). Same DISTINCT grain as the table below.
Download these 15 declarations as CSV . FEMA source data is public domain; our derived presentation is CC0.
| DR# | Title | Type | Incident | Date |
|---|---|---|---|---|
| 4489 | COVID-19 PANDEMIC | DR | Biological | 2020-03-26 |
| 3435 | COVID-19 | EM | Biological | 2020-03-13 |
| 4461 | SEVERE STORMS AND FLOODING | DR | Flood | 2019-09-19 |
| 4116 | SEVERE STORMS, STRAIGHT-LINE WINDS, AND FLOODING | DR | Flood | 2013-05-10 |
| 1960 | SEVERE WINTER STORM AND SNOWSTORM | DR | Snowstorm | 2011-03-17 |
| 1771 | SEVERE STORMS AND FLOODING | DR | Severe Storm | 2008-06-24 |
| 3230 | HURRICANE KATRINA EVACUATION | EM | Hurricane | 2005-09-07 |
| 1368 | FLOODING | DR | Flood | 2001-05-09 |
| 3134 | IL-WINTER STORM 1/1/99 | EM | Snowstorm | 1999-01-08 |
| 997 | SEVERE STORMS & FLOODING | DR | Flood | 1993-07-09 |
| 3068 | BLIZZARDS & SNOWSTORMS | EM | Snowstorm | 1979-01-16 |
| 438 | SEVERE STORMS & FLOODING | DR | Flood | 1974-06-10 |
| 373 | SEVERE STORMS & FLOODING | DR | Flood | 1973-04-26 |
| 262 | FLOODING | DR | Flood | 1969-06-06 |
| 194 | TORNADOES, SEVERE STORMS & FLOODING | DR | Tornado | 1965-04-25 |
Storm Events in Illinois
Statewide NOAA context only. PlainHazard does not currently attribute these state totals to Mercer County.
| Storm Type | Events | Fatalities | Injuries | Property Damage |
|---|---|---|---|---|
| Thunderstorm Wind | 7,218 | 9 | 67 | $46.0M |
| Hail | 3,195 | 0 | 0 | $27.1M |
| Winter Weather | 1,363 | 14 | 49 | $1.8M |
| Flood | 1,221 | 14 | 11 | $84.3M |
| Flash Flood | 1,133 | 11 | 3 | $1.1B |
Source: NOAA Storm Events Database State-level aggregated data, 2015-2025
NFIP Flood Insurance Claims
Total Claims
61
Total Paid
$1.4M
Avg Per Claim
$22.2K
Source: FEMA National Flood Insurance Program (NFIP) OpenFEMA Claims Data
FEMA National Risk Index
Overall Risk
Very Low
Score: 8.8/100
Expected Annual Loss
Very Low
$6.9M/year
Social Vulnerability
Very Low
Community Resilience
Very High
Hazard Risk Breakdown
Drought Relatively Moderate
Landslide Relatively Low
Ice Storm Relatively Moderate
Strong Wind Relatively Moderate
Lightning Relatively Moderate
Heat Wave Relatively Low
Cold Wave Relatively Low
Hail Very Low
Winter Weather Relatively Low
Earthquake Very Low
Tornado Very Low
Hurricane Very Low
Riverine Flooding Very Low
Wildfire Very Low
Source: FEMA National Risk Index (NRI) Ratings reflect relative scores among all US counties. Data: hazards.fema.gov/nri
The model's sharpest exposure here: Drought
Drought is the slowest of the modeled hazards and the least visible: it does its damage to agriculture, water supply and soil over seasons rather than hours, so it rarely produces the kind of single-day damage that drives a disaster declaration. FEMA scores it in event-days per year rather than discrete events for exactly that reason.
Worth noting for Mercer County: the model and the federal record do NOT point at the same hazard. Drought carries the highest modeled rating (Relatively Moderate), while the county's declaration history is led by Flood. That is not a contradiction, the two measure genuinely different things. Declarations record federal ACTION, which requires damage costly enough to exceed state and local capacity; the Risk Index models EXPECTED annual loss across all 18 hazards whether or not any declaration ever followed. A hazard can be the county's largest modeled exposure and never once have driven a declaration.
National Risk Index ratings are modeled estimates of expected annual loss, not predictions of what will happen in any given year.
Data-matched county comparisons
Mercer County's closest FEMA peer: Union County, IN
Comparisons use published FEMA declaration fields plus the National Risk Index composite for Mercer County. Record similarity, not a safety rating.
Closest declaration profiles
Mercer County shows 15 FEMA declarations, led by Flood.
Similar Major-disaster share
Mercer County: 11 of 15 of its declarations are Major.
Similar modeled NRI score
Mercer County: NRI composite 8.8 (Very Low).
How these peers are chosen
Cohort: Published U.S. county equivalents outside the source state or territory. Each metric keeps six ETL candidates; three unique destinations are shown after de-duplicating across axes. Declaration-volume ranking combines count and Major-disaster share and prefers a different leading incident type; Major-share ranks the Major fraction adjusted for volume; NRI ranks the modeled composite score only.
Retained FEMA snapshot feed for Mercer County - capture-dated entries only.
Further reading for this county
Understanding disaster data
Mercer County's NFIP claims file (61 claims) and FEMA declaration history measure different federal records - this guide separates them from modeled NRI risk.
More PlainHazard guides
- Most disaster-prone counties - U.S. counties ranked by FEMA declaration totals.
- Understanding disaster data - declarations vs storm events vs NRI scores.
- Preparing for natural disasters - household checklist (not county-specific advice).
Related
Frequently Asked Questions
What is the most common disaster type in Mercer County?
The most common disaster type in Mercer County is Flood, with 7 declarations. Other disaster types include Snowstorm (3), Biological (2), Severe Storm (1).
How does Mercer County's FEMA declaration record compare with the Illinois average?
FEMA lists 15 declaration records for Mercer County. That is 17% above the Illinois county mean of 12.9. Its count is also 28% below the national county mean of 20.7. A larger declaration history records more federal actions; it is not a forecast of the county's next hazard.
How many major FEMA disaster declarations has Mercer County received?
Mercer County has received 11 major disaster declarations, representing 73% of all 15 disaster declarations.
How many flood insurance claims has Mercer County filed?
Mercer County has 61 National Flood Insurance Program (NFIP) claims totaling $1.4M in payments, with an average of $22.2K per claim.
Does FEMA's top risk-rated hazard match the highest Expected Annual Loss in Mercer County?
No. In Mercer County, Drought has the highest National Risk Index rating (Relatively Moderate), while Riverine Flooding leads Expected Annual Loss at about $2.0M. FEMA's risk score and dollar-loss model use different inputs, so the leaders often differ.
What was the worst year for disasters in Mercer County?
The most active year for disaster declarations in Mercer County was 2020, with 2 declarations. The county has FEMA disaster data spanning 1965 to 2020.
What is the FEMA National Risk Index score for Mercer County?
According to the FEMA National Risk Index, Mercer County, Illinois has an overall risk score of 8.8 out of 100 (Very Low). The county's social vulnerability rating is Very Low and community resilience is Very High. The Expected Annual Loss (EAL) score is Very Low, representing $6.9M in annualized losses.
Which natural hazard poses the greatest risk to Mercer County?
Based on FEMA NRI data, the highest-risk natural hazard in Mercer County is Drought (risk rating: Relatively Moderate). Other significant hazards include Landslide (Relatively Low) and Ice Storm (Relatively Moderate). FEMA's modeled event frequency puts drought here at 8.2 modeled event-days per year, drawn from 217 historical events on record. These scores are based on FEMA's analysis of historical event frequency, exposed assets, and community vulnerability.
Data Sources & Methodology
Disaster declaration data comes from the FEMA OpenFEMA Disaster Declarations Summaries v2 API, which includes all federally declared disasters, emergencies, and fire management assistance grants.
Storm event data is sourced from the NOAA Storm Events Database (2015-2025), which tracks significant weather events including thunderstorms, tornadoes, floods, and winter storms.
Flood insurance data comes from the FEMA National Flood Insurance Program (NFIP) OpenFEMA claims dataset.
This data is provided for informational purposes only. FEMA disaster declarations represent federal response actions and may not capture all local emergencies or weather events.
What this means for Mercer County
Mercer County, IL has 15 federal declaration records, 17% more than the Illinois county mean of 13; its history sits in PlainHazard's high activity band.
- Within this above-state-average declaration file, major disaster leads with 11 of 15 records; the category describes past federal action, not the next likely hazard. Illinois overview
- The state benchmark and national rank point the same way: this count tops the Illinois mean and the totals for 23% of 3,266 U.S. counties. Most-disaster rankings
- Use the data guide to separate this mid-volume insurance-claims file from declaration counts and modeled NRI risk. Disaster-data guide
An above-average declaration count records past federal responses; it does not predict the next event. Current warnings come from the National Weather Service and local emergency officials.
PlainHazard derives this profile from FEMA's Disaster Declarations Summaries and National Risk Index data. The declaration comparison covers 3,266 U.S. counties and county equivalents in this database, refreshed as of 2026-08-03. Read our methodology - how this data is sourced, computed, and verified.
All federal data sources used on this page
- FEMA OpenFEMA, Disaster Declarations Summaries v2 - all federally-declared disasters for this county. fema.gov/openfema/disaster-declarations
- FEMA National Risk Index (NRI) - per-county per-hazard risk ratings and expected annual loss. hazards.fema.gov/nri
- NOAA NCEI Storm Events Database - state-level storm/severe-weather event records, 2015-2025. ncdc.noaa.gov/stormevents
Data sourced from official public datasets. See our methodology for details. Retrieved and formatted by PlainHazard Editorial
Verify with FEMA → · Verify with FEMA NRI → · Verify with NOAA →
Every figure on PlainHazard is rendered directly from FEMA federal disaster data, no number is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or national statistics report, the data & editorial changelog, or report a data error.