Rivers in Illinois

Fox River at Algonquin tailwater

McHenry County, IllinoisNWS AFBI2USGS 05550001Romeoville office

Below flood stage
8.30ftStage

Observed Mon, Sep 21, 11:30 PM CDT

Flood stage
9.50 ft
Forecast crest
8.80 ftFri, Sep 25, 7:00 PM CDT
Record crest
14.00 ft1938

Open the live map with the river flood outlook

Flood stages and impacts

CategoryStage
Major flood12.00 ft
Moderate flood10.50 ft
Minor flood9.50 ft
Action9.00 ft
  1. 18.00 ftInundation of the floodplain reaches more than 1 block from the river in Algonquin.
  2. 17.50 ftMain Street is threatened in Algonquin.
  3. 16.50 ftIL-176 threatened near Holiday Hills.
  4. 16.00 ftNumerous structures are threatened along Main Street in Algonquin. North Water Reclamation Facility property in Elgin is threatened.
  5. 15.50 ftAlgonquin Road (IL-62) is threatened west of the river in Algonquin.
  6. 15.00 ftInundation reaches up to 2 blocks from the river in Willow Lake Estates in Elgin. Railroad tracks are threatened in downtown Elgin. Multiple structures threatened in downtown Carpentersville. Duncan Avenue threatened north of Elgin.
  7. 14.50 ftWidespread inundation of roadways and structures reaches 2 blocks from the river near Freeman Park north of downtown East Dundee. A few structures threatened along 1st Street in West Dundee.
  8. 14.00 ftResidences threatened along Riverview Drive and Holiday Drive in Holiday Hills. Residences threatened along Riverside Drive West south of McHenry. Structures threatened along North Harrison Street in Algonquin. A few structures threatened along Washington Street in Carpentersville. Algonquin Wastewater Treatment Facility property threatened. Main Street threatened in Carpentersville.
  9. 13.50 ftBackwater causes Crystal Creek to threaten structures near the village hall in Algonquin. Multiple structures threatened along Wenholz Avenue, Michigan Avenue, North Street, Barrington Avenue, and 2nd Street in East Dundee.
  10. 13.00 ftA few structures threatened along Water Street in East Dundee. A few structures threatened along 2nd Street in West Dundee. Structures along Riverside Drive and Grove Ave are threatened in Elgin. Backwater causes Crystal Creek to threaten low-lying sections of Towne Park in Algonquin.
  11. 12.50 ftResidences threatened along Edwards Avenue in East Dundee. Prairie Trail is threatened at the river in Algonquin. Parking lots threatened in downtown Carpentersville. Low-lying parking lots threatened at Judson College in Elgin.
  12. 12.00 ftStructures threatened along River Street, Johnson Street, and Maiden Lane in East Dundee. North Harrison Street threatened near Riverside Park in Algonquin. Washington Street threatened in Carpentersville. Water Street, Edwards Avenue, and Elgin Avenue threatened in East Dundee. Bayview Road threatened in Elgin. Low-lying areas of Festival Park are threatened in Elgin.
  13. 11.50 ftResidences threatened along Oceola Drive in Algonquin. A few residences threatened along McBride Street in Elgin. Jayne Street and Beach Drive threatened in Algonquin. River Street threatened in East Dundee. Jerusha Avenue threatened in Elgin. Fox River Trail threatened between East Dundee and Elgin.
  14. 11.00 ftStructures threatened near Elgin Avenue and Corey Street south of East Dundee. Lincoln Avenue threatened in West Dundee. Filip Street and Fox River Drive threatened in Algonquin. Fox River Trail threatened south of downtown Elgin.
  15. 10.50 ftStructures threatened along Fox River Drive in East Dundee. Parking lots threatened in downtown West Dundee. Low-lying sections of Cornish Park are inundated in Algonquin. Low-lying sections of Trout Park inundated north of Elgin.
  16. 10.00 ftWinaki Trail and Onaway Trail are threatened south of Algonquin. Athletic fields inundated at Judson College in Elgin.
  17. 9.50 ftFox River Drive threatened in East Dundee. Boathouses threatened along the river in Cary.
  18. 9.00 ftWater overflows low-lying river banks along Grove Street in Valley View, along River Shore Drive in Cary, and along Riverview Drive and Holiday Drive in Holiday Hills.
  19. 8.00 ftLow-lying trails threatened at Walton Island Park in Elgin.

Flood outlook

Chance of flooding, September to November

CategoryChance
Minor flooding15%
Moderate flooding11%
Major floodingUnder 5%

The three-month chances are the River Forecast Centers’ long-range flood outlook, issued August 28, 2026.

Crest history

29 crests on NOAA’s list since 1938.

#DateStage
1July 5, 193814.00 ft
2April 6, 196013.70 ft
3July 23, 201713.18 ft
4April 23, 201312.70 ft
5March 24, 194812.50 ft
6March 31, 196212.40 ft
7June 26, 201811.85 ft
8May 23, 202011.83 ft
9September 17, 201911.38 ft
10June 26, 201311.01 ft
11October 11, 201910.78 ft
12March 20, 201910.58 ft
13October 10, 201810.57 ft
14May 12, 201910.55 ft
15May 3, 202010.55 ft
16April 9, 202410.42 ft
17June 5, 201910.37 ft
18May 13, 201010.01 ft
19September 6, 20189.92 ft
20May 3, 20179.89 ft
21February 28, 20189.87 ft
22May 21, 20189.76 ft
23April 4, 20239.58 ft
24October 31, 20199.54 ft
25July 18, 20249.43 ft

Most recent crests

  • July 18, 2024: 9.43 ft
  • April 9, 2024: 10.42 ft
  • April 4, 2023: 9.58 ft
  • March 3, 2023: 9.11 ft
  • May 23, 2020: 11.83 ft
  • May 3, 2020: 10.55 ft
  • October 31, 2019: 9.54 ft
  • October 11, 2019: 10.78 ft
  • September 17, 2019: 11.38 ft
  • June 5, 2019: 10.37 ft

Nearby

Upstream, downstream and the gauges around this one.

What this means

Forecasts by the North Central River Forecast Center. Forecasts are issued as needed during times of high water, but are not routinely available. River forecasts for this location take into account past and future precipitation. The stages/flows that will occur may be different if future rainfall is different than forecast.

Sources

Stage, flood stages, impacts and crest history from NOAA’s National Water Prediction Service. Streamflow and the daily record from the U.S. Geological Survey.