Iroquois County, Illinois

What hazards hit Iroquois County most?

The most frequent records are severe thunderstorm wind events: 237 since 1958. 55% of its severe thunderstorm wind events since 1958 fell in May and June. The rank column places the county among Illinois's counties by days with a record per 1,000 square miles of land over each hazard's complete period.

Source: NOAA NCEI Storm Events Database (county and forecast-zone records attributed to the county; a zone record shows its own totals on each county it covers). Days: dates with at least one record of the hazard in the county. Ranks: days with a record per 1,000 square miles of land (Census Bureau 2024 Gazetteer), since 1950 for tornadoes, 1955 for hail and thunderstorm wind, 1996 for the rest.

How many tornadoes has Iroquois County had?

NOAA records 64 tornadoes in Iroquois County from 1954 to 2026, the strongest rated F3, with 0 deaths and 11 injuries recorded in the county. A tornado that crossed a county line is counted in each county it touched, with the length of its path inside the county.

Counted as whole tornadoes rather than county records, the Storm Prediction Center's database holds 58 tornadoes whose track touched Iroquois County since 1950 (NOAA's county records number 64: they file a crossing tornado once per county segment, and the two databases differ on some tracks); along their whole tracks they killed 0 people.

Map of the strongest tornado tracks in Illinois.

Source: NOAA NCEI Storm Events Database, tornado records by county (path length in the county, maximum width); ratings as published: F scale before February 1, 2007, EF scale after. Whole-track figures: NOAA Storm Prediction Center tornado database (1950-2025). SPC severe weather database.

When was the last damaging storm in Iroquois County?

The most recent record with damage, injuries or deaths is the October 5, 2025 wildfire ($10,000 in damage in 2025 dollars).

Source: NOAA NCEI Storm Events Database; every record of 2025-2026 is listed, earlier ones when they caused deaths, injuries or $250,000 of damage (2025 dollars), and every tornado.

The deadliest and costliest records

A damage figure marked "step" is a record from before 1993: NOAA then filed damage by category, and the figure is the category as entered, in the dollars of that year, not an estimate of the loss.

Source: NOAA NCEI Storm Events Database: deaths and injuries direct and indirect; damage is property plus crops as estimated by the National Weather Service, converted to 2025 dollars.

Is it getting more frequent?

Records per decade for Iroquois County's most frequent hazards. Counts rose everywhere after 1996, when NOAA began recording every event type, so compare decades within a hazard's complete period only (the shaded cells come before it).

Source: NOAA NCEI Storm Events Database, records per calendar decade; zone records from the CZ_TYPE field (Z).

What time of year?

55% of its severe thunderstorm wind events since 1958 fell in May and June. The two busiest months are in violet.

Source: NOAA NCEI Storm Events Database, records by the month they began.

Federal disaster declarations for Iroquois County

FEMA's register lists 9 declarations that include Iroquois County: 5 major disasters, 4 emergencies and 0 fire management assistance declarations. Most were for biological (2) and severe storm (2).

Source: FEMA OpenFEMA Disaster Declarations Summaries (v2), declarations through October 2, 2026; one declaration is counted once however many areas it names. OpenFEMA dataset page.

How many floods has Iroquois County had?

NOAA's Storm Events Database holds 54 flood or flash flood records for Iroquois County from 1996 to 2023, on 39 days, with 0 deaths. By flood insurance claims since 1978 (OpenFEMA, as of September 8, 2026), Iroquois County ranks 364th of 2,942 U.S. counties.

The National Flood Insurance Program has paid $16.9 million on 840 claims filed in Iroquois County; the most in one year was 363 in 2008. Claims count insured losses only: uninsured flood damage is not in this file.

Source: FEMA OpenFEMA NFIP Redacted Claims, as of September 8, 2026; claims by year of loss, payments in the dollars of the year paid. OpenFEMA dataset page.

FEMA's modeled risk for Iroquois County

FEMA's National Risk Index rates Iroquois County Relatively Low overall, with an expected annual loss of $33.9 million. These are FEMA's model estimates of future loss from 18 hazards, not a count of what happened; they can differ from the record above.

Source: FEMA National Risk Index, county table, December 2025 release. FEMA's National Risk Index map.

Counties that share a border with Iroquois County

1. Vermilion County 830
2. Kankakee County 698
3. Iroquois County 564
4. Ford County 380
5. Newton County, IN 317
6. Benton County, IN 309

Source: U.S. Census Bureau county adjacency file; NOAA NCEI Storm Events Database, records since 1950. The Census Bureau's adjacency file.

Next

• Tornadoes in IllinoisEvery Illinois tornado since 1950 and the counties with the most per square mile
• Severe thunderstorm wind in IllinoisThe state's severe thunderstorm wind events, by county, year and month
• The Illinois recordEvery hazard in the state, its deadliest events and its federal declarations
• FEMA's risk rating for each hazard in Iroquois CountyThe hazard risk calculator: 18 hazards beside the county's record
• Download Iroquois County's FEMA declarations (CSV)9 rows: every declaration that named the county, for your own analysis