Search
Menu

Explore

Hazards

Analysis

Rankings

Reference

Fox River at Algonquin

Highest listed crest 4.50 ftFlood stage 3.0 ft81 crests since 1916

The Fox River at Algonquin crested at major flood stage 12 times among the 81 crests the National Weather Service lists from 1916 to 2020. The highest, 4.50 ft on April 1, 1916, was major flooding, 1.50 feet above flood stage.

The gauge

Highest listed crest
4.50 ft
April 1, 1916
Flood stage
3.0 ft
Major flooding from 4.0 ft
Crests at major
12
21st of 177 gauges in Illinois
Most recent flood crest
May 23, 2020
3.16 ft, minor flooding
Location
McHenry County
Near Lake in the Hills (1.6 mi), Algonquin (1.7 mi), Carpentersville (3.0 mi)

Flood stages

The thresholds the National Weather Service uses for this gauge today, and how many listed crests reached each.

Flood categories, Fox River at Algonquin
Action stage2.817Sep 17, 2019The level at which the NWS or its partners begin to take action
Flood stage (minor)3.017May 23, 2020Minimal or no property damage, but possibly some public threat
Moderate flood stage3.319Aug 25, 2007Some inundation of structures and roads near the stream
Major flood stage4.012Jul 23, 2017Extensive inundation of structures and roads

Every listed crest

81 crests from 1916 to 2020. Filled: at or above flood stage. Hover a crest for its date and stage.

Listed crests at the Fox River at Algonquin, 1916 to 2020 22.533.544.5ft Flood stage 3.0 ftMajor 4.0 ft Apr 1, 1916: 4.50 ft, major floodingMar 28, 1917: 2.80 ft, action stage; 2,260 cubic feet per secondMar 6, 1918: 4.40 ft, major flooding; 5,750 cubic feet per secondMar 21, 1919: 4.00 ft, major flooding; 4,800 cubic feet per secondMar 30, 1920: 4.16 ft, major flooding; 5,050 cubic feet per secondMay 1, 1921: 4.15 ft, major flooding; 4,950 cubic feet per secondApr 15, 1922: 3.04 ft, minor flooding; 2,820 cubic feet per secondApr 13, 1923: 3.30 ft, moderate flooding; 3,280 cubic feet per secondApr 4, 1924: 3.50 ft, moderate flooding; 3,660 cubic feet per secondFeb 26, 1925: 2.44 ft, below flood stage; 1,880 cubic feet per secondApr 22, 1926: 2.92 ft, action stage; 2,620 cubic feet per secondFeb 16, 1927: 3.01 ft, minor flooding; 2,720 cubic feet per secondApr 10, 1928: 3.17 ft, minor flooding; 3,080 cubic feet per secondMar 16, 1929: 4.37 ft, major flooding; 5,450 cubic feet per secondFeb 27, 1930: 2.69 ft, below flood stage; 2,260 cubic feet per secondApr 2, 1932: 2.47 ft, below flood stage; 1,880 cubic feet per secondMay 14, 1933: 3.37 ft, moderate flooding; 3,470 cubic feet per secondMar 13, 1935: 3.07 ft, minor flooding; 2,840 cubic feet per secondMar 16, 1936: 3.02 ft, minor flooding; 2,750 cubic feet per secondMar 8, 1937: 3.32 ft, moderate flooding; 3,300 cubic feet per secondJul 5, 1938: 4.42 ft, major flooding; 5,630 cubic feet per secondSep 2, 1940: 2.86 ft, action stage; 2,540 cubic feet per secondMar 26, 1941: 2.90 ft, action stage; 2,620 cubic feet per secondMar 20, 1942: 2.81 ft, action stage; 2,470 cubic feet per secondMar 20, 1943: 3.75 ft, moderate flooding; 4,640 cubic feet per secondMar 18, 1944: 3.46 ft, moderate flooding; 3,970 cubic feet per secondMay 17, 1945: 2.58 ft, below flood stage; 2,300 cubic feet per secondMar 18, 1946: 3.35 ft, moderate flooding; 3,760 cubic feet per secondJun 7, 1947: 2.50 ft, below flood stage; 2,500 cubic feet per secondMar 24, 1948: 3.48 ft, moderate flooding; 4,680 cubic feet per secondMar 9, 1949: 2.52 ft, below flood stage; 2,580 cubic feet per secondApr 29, 1950: 2.87 ft, action stage; 3,310 cubic feet per secondMar 9, 1951: 3.15 ft, minor flooding; 3,900 cubic feet per secondMar 25, 1952: 3.29 ft, minor flooding; 4,400 cubic feet per secondApr 28, 1954: 2.46 ft, below flood stage; 2,400 cubic feet per secondJun 15, 1955: 2.49 ft, below flood stage; 2,470 cubic feet per secondApr 3, 1959: 2.83 ft, action stage; 3,340 cubic feet per secondApr 6, 1960: 4.01 ft, major flooding; 6,610 cubic feet per secondMar 19, 1961: 2.53 ft, below flood stage; 2,760 cubic feet per secondMar 31, 1962: 3.37 ft, moderate flooding; 4,870 cubic feet per secondApr 13, 1965: 2.98 ft, action stage; 3,910 cubic feet per secondFeb 16, 1966: 2.86 ft, action stage; 3,600 cubic feet per secondJun 17, 1967: 3.00 ft, minor flooding; 3,960 cubic feet per secondJun 11, 1969: 2.56 ft, below flood stage; 2,690 cubic feet per secondJun 5, 1970: 2.69 ft, below flood stage; 3,020 cubic feet per secondMar 6, 1971: 3.05 ft, minor flooding; 3,920 cubic feet per secondSep 24, 1972: 3.35 ft, moderate flooding; 4,700 cubic feet per secondMay 4, 1973: 3.71 ft, moderate flooding; 5,730 cubic feet per secondMar 12, 1974: 4.01 ft, major flooding; 5,310 cubic feet per secondMar 27, 1975: 2.86 ft, action stage; 3,440 cubic feet per secondMar 10, 1976: 3.23 ft, minor flooding; 4,380 cubic feet per secondJul 7, 1978: 2.77 ft, below flood stage; 3,210 cubic feet per secondApr 2, 1979: 4.00 ft, major flooding; 6,610 cubic feet per secondSep 19, 1980: 2.49 ft, below flood stage; 2,530 cubic feet per secondApr 15, 1981: 2.47 ft, below flood stage; 2,480 cubic feet per secondApr 5, 1982: 3.10 ft, minor flooding; 4,040 cubic feet per secondApr 11, 1983: 3.51 ft, moderate flooding; 5,150 cubic feet per secondFeb 18, 1984: 2.70 ft, below flood stage; 3,030 cubic feet per secondMar 8, 1985: 3.22 ft, minor flooding; 4,350 cubic feet per secondMar 19, 1986: 3.12 ft, minor flooding; 3,780 cubic feet per secondOct 3, 1987: 3.99 ft, moderate flooding; 6,170 cubic feet per secondFeb 3, 1988: 2.81 ft, action stage; 3,030 cubic feet per secondMar 18, 1990: 2.83 ft, action stageApr 17, 1991: 2.82 ft, action stage; 3,390 cubic feet per secondApr 23, 1993: 3.75 ft, moderate flooding; 6,150 cubic feet per secondMar 7, 1994: 3.05 ft, minor flooding; 3,910 cubic feet per secondMay 23, 1996: 3.25 ft, minor flooding; 4,570 cubic feet per secondFeb 24, 1997: 2.89 ft, action stage; 3,550 cubic feet per secondApr 22, 1998: 2.65 ft, below flood stage; 2,930 cubic feet per secondJun 17, 1999: 3.30 ft, moderate flooding; 4,710 cubic feet per secondJun 17, 2000: 3.42 ft, moderate flooding; 5,080 cubic feet per secondFeb 16, 2001: 2.88 ft, action stage; 3,250 cubic feet per secondOct 27, 2002: 3.33 ft, moderate flooding; 3,960 cubic feet per secondMay 22, 2004: 3.32 ft, moderate flooding; 6,720 cubic feet per secondAug 25, 2007: 3.51 ft, moderate flooding; 6,700 cubic feet per secondJun 19, 2008: 2.99 ft, action stage; 6,080 cubic feet per secondApr 23, 2013: 4.03 ft, major floodingJul 23, 2017: 4.39 ft, major flooding; 8,322 cubic feet per secondJun 26, 2018: 3.09 ft, minor floodingSep 17, 2019: 2.97 ft, action stageMay 23, 2020: 3.16 ft, minor flooding Highest, 4.50 ft, Apr 1, 1916 192019401960198020002020

Crests at or above flood stage, by decade

Crests at or above flood stage per decade, Fox River at Algonquin 1910s: 3 1920s: 8 8 1930s: 5 1940s: 4 1950s: 2 1960s: 3 1970s: 6 1980s: 5 1990s: 4 2000s: 4 2010s: 3 2020s: 1 1910s1920s1930s1940s1950s1960s1970s1980s1990s2000s2010s2020s
  1. These are the crests the local National Weather Service office lists for the gauge: the highest on record and recent crests. Lesser floods between them may be missing, so counts by decade are a floor.
  2. Categories use today's flood stages. Levees, dams and channel changes since a crest can make old and new stages not directly comparable.

Highest crests

The 50 highest of 81 listed crests.

Highest listed crests, Fox River at Algonquin
1Apr 1, 19164.50+1.50Major—
2Jul 5, 19384.42+1.42Major5,630
3Mar 6, 19184.40+1.40Major5,750
4Jul 23, 20174.39+1.39Major8,322
5Mar 16, 19294.37+1.37Major5,450
6Mar 30, 19204.16+1.16Major5,050
7May 1, 19214.15+1.15Major4,950
8Apr 23, 20134.03+1.03Major—
9Apr 6, 19604.01+1.01Major6,610
10Mar 12, 19744.01+1.01Major5,310
11Mar 21, 19194.00+1.00Major4,800
12Apr 2, 19794.00+1.00Major6,610
13Oct 3, 19873.99+0.99Moderate6,170
14Mar 20, 19433.75+0.75Moderate4,640
15Apr 23, 19933.75+0.75Moderate6,150
16May 4, 19733.71+0.71Moderate5,730
17Apr 11, 19833.51+0.51Moderate5,150
18Aug 25, 20073.51+0.51Moderate6,700
19Apr 4, 19243.50+0.50Moderate3,660
20Mar 24, 19483.48+0.48Moderate4,680
21Mar 18, 19443.46+0.46Moderate3,970
22Jun 17, 20003.42+0.42Moderate5,080
23May 14, 19333.37+0.37Moderate3,470
24Mar 31, 19623.37+0.37Moderate4,870
25Mar 18, 19463.35+0.35Moderate3,760
26Sep 24, 19723.35+0.35Moderate4,700
27Oct 27, 20023.33+0.33Moderate3,960
28Mar 8, 19373.32+0.32Moderate3,300
29May 22, 20043.32+0.32Moderate6,720
30Apr 13, 19233.30+0.30Moderate3,280
31Jun 17, 19993.30+0.30Moderate4,710
32Mar 25, 19523.29+0.29Minor4,400
33May 23, 19963.25+0.25Minor4,570
34Mar 10, 19763.23+0.23Minor4,380
35Mar 8, 19853.22+0.22Minor4,350
36Apr 10, 19283.17+0.17Minor3,080
37May 23, 20203.16+0.16Minor—
38Mar 9, 19513.15+0.15Minor3,900
39Mar 19, 19863.12+0.12Minor3,780
40Apr 5, 19823.10+0.10Minor4,040
41Jun 26, 20183.09+0.09Minor—
42Mar 13, 19353.07+0.07Minor2,840
43Mar 6, 19713.05+0.05Minor3,920
44Mar 7, 19943.05+0.05Minor3,910
45Apr 15, 19223.04+0.04Minor2,820
46Mar 16, 19363.02+0.02Minor2,750
47Feb 16, 19273.01+0.01Minor2,720
48Jun 17, 19673.000.00Minor3,960
49Jun 19, 20082.99−0.01Action6,080
50Apr 13, 19652.98−0.02Action3,910

The worst floods along the Fox River

For this gauge's highest crests, the other gauges on the Fox River that crested above flood stage within a week.

July 5, 1938: 4.42 ft here, major flooding

July 23, 2017: 4.39 ft here, major flooding

Gauges on the Fox River

Flood gauges sharing the river's name, linked within 80 miles of one another.

Flood gauges on the Fox River
Algonquin this gaugeIL3.04.50 ft, Apr 1, 191612
Algonquin tailwaterIL9.514.00 ft, Jul 5, 19386
BurlingtonWI11.016.15 ft, Jul 13, 20171
DaytonIL12.036.47 ft, Jan 25, 19605
ElginIL713.0713.11 ft, Jul 24, 20170
Fox LakeIL6.08.12 ft, Apr 5, 19606
Lake VillaIL6.08.90 ft, Jul 4, 19387
McHenry (Stratton Lock and Dam) tailwaterIL4.09.00 ft, Jul 5, 19386
MontgomeryIL13.516.50 ft, Jul 18, 19961
RochesterWI6.06.29 ft, Apr 21, 20260
South Elgin DamIL14.515.04 ft, Apr 18, 20130
WaukeshaWI6.08.85 ft, Jun 9, 20080
Yorkville (Palmer Dam)IL15.521.00 ft, Jul 18, 19961
AntiochIL6.08.34 ft, Apr 5, 19606
JohnsburgIL6.58.90 ft, Jul 4, 19382
New MunsterWI11.017.47 ft, Jul 13, 20175

Other gauges in McHenry County

Flood gauges in McHenry County
Mchenry7.07.48 ft, Jun 26, 20130
Algonquin tailwater9.514.00 ft, Jul 5, 19386
McHenry (Stratton Lock and Dam) tailwater4.09.00 ft, Jul 5, 19386
Johnsburg6.58.90 ft, Jul 4, 19382
Marengo12.013.06 ft, Sep 4, 20180
Wonder Lake9.014.30 ft, Jun 11, 19671
Spring Grove11.014.26 ft, Sep 26, 19860

McHenry County: every hazard · River floods across the country · Illinois

NOAA National Water Prediction Service, gauge ALGI2, retrieved October 30, 2026. Stages in feet on the gauge's own datum, not elevation. Crests are as the National Weather Service lists them; preliminary values may be revised.