Fox River near Johnsburg

Highest listed crest 8.90 ftFlood stage 6.5 ft14 crests since 1938

The Fox River near Johnsburg crested at major flood stage 2 times among the 14 crests the National Weather Service lists from 1938 to 2020. The highest, 8.90 ft on July 4, 1938, was major flooding, 2.40 feet above flood stage. 4 other gauges on the Fox River crested above flood stage within a week of it, 3 at their own highest listed crest.

The gauge

Highest listed crest: 8.90 ft; July 4, 1938
Flood stage: 6.5 ft; Major flooding from 7.5 ft
Crests at major: 2; 82nd of 177 gauges in Illinois
Most recent flood crest: July 17, 2017; 7.37 ft, moderate flooding
Location: McHenry County; Near McHenry (3.9 mi), Fox Lake (4.5 mi), Round Lake (7.2 mi)
Identifiers: NWS JHNI2; USGS 05548500

Flood stages

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

Flood categories, Fox River near Johnsburg

Action stage	6.0	6	May 23, 2020	The level at which the NWS or its partners begin to take action
Flood stage (minor)	6.5	2	Jun 18, 2008	Minimal or no property damage, but possibly some public threat
Moderate flood stage	7.0	4	Jul 17, 2017	Some inundation of structures and roads near the stream
Major flood stage	7.5	2	Apr 6, 1960	Extensive inundation of structures and roads

Every listed crest

14 crests from 1938 to 2020. Filled: at or above flood stage. Hover a crest for its date and stage.

Crests at or above flood stage, by decade

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.
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

Highest listed crests, Fox River near Johnsburg

1	Jul 4, 1938	8.90	+2.40	Major	—
2	Apr 6, 1960	7.55	+1.05	Major	—
3	Apr 22, 2013	7.47	+0.97	Moderate	—
4	Jul 17, 2017	7.37	+0.87	Moderate	—
5	Oct 3, 1986	7.10	+0.60	Moderate	—
6	Apr 2, 1979	7.07	+0.57	Moderate	—
7	Apr 23, 1993	6.65	+0.15	Minor	—
8	Jun 18, 2008	6.50	0.00	Minor	—
9	Mar 11, 1974	6.48	−0.02	Action	—
10	Aug 27, 2007	6.39	−0.11	Action	—
11	Sep 17, 2019	6.26	−0.24	Action	—
12	Sep 26, 1972	6.14	−0.36	Action	—
13	May 23, 2020	6.10	−0.40	Action	—
14	Jun 3, 2000	6.06	−0.44	Action	—

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 4, 1938: 8.90 ft here, major flooding

Algonquin tailwaterIL · Jul 5, 1938 · 14.00 ft · Major · its highest
McHenry (Stratton Lock and Dam) tailwaterIL · Jul 5, 1938 · 9.00 ft · Major · its highest
Lake VillaIL · Jul 4, 1938 · 8.90 ft · Major · its highest
AlgonquinIL · Jul 5, 1938 · 4.42 ft · Major

April 6, 1960: 7.55 ft here, major flooding

Algonquin tailwaterIL · Apr 6, 1960 · 13.70 ft · Major
AntiochIL · Apr 5, 1960 · 8.34 ft · Major · its highest
Lake VillaIL · Apr 6, 1960 · 8.18 ft · Major
Fox LakeIL · Apr 5, 1960 · 8.12 ft · Major · its highest
McHenry (Stratton Lock and Dam) tailwaterIL · Apr 5, 1960 · 7.00 ft · Major
AlgonquinIL · Apr 6, 1960 · 4.01 ft · Major
WaukeshaWI · Apr 1, 1960 · 8.00 ft · Moderate
South Elgin DamIL · Apr 7, 1960 · 14.70 ft · Minor

April 22, 2013: 7.47 ft here, moderate flooding

New MunsterWI · Apr 20, 2013 · 14.50 ft · Major
Algonquin tailwaterIL · Apr 23, 2013 · 12.70 ft · Major
AntiochIL · Apr 22, 2013 · 8.09 ft · Major
Fox LakeIL · Apr 22, 2013 · 7.91 ft · Major
Lake VillaIL · Apr 22, 2013 · 7.88 ft · Major
McHenry (Stratton Lock and Dam) tailwaterIL · Apr 23, 2013 · 7.64 ft · Major
AlgonquinIL · Apr 23, 2013 · 4.03 ft · Major
DaytonIL · Apr 19, 2013 · 20.70 ft · Moderate
MontgomeryIL · Apr 18, 2013 · 15.14 ft · Moderate
South Elgin DamIL · Apr 18, 2013 · 15.04 ft · Moderate · its highest

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	IL	3.0	4.50 ft, Apr 1, 1916	12
Algonquin tailwater	IL	9.5	14.00 ft, Jul 5, 1938	6
Burlington	WI	11.0	16.15 ft, Jul 13, 2017	1
Dayton	IL	12.0	36.47 ft, Jan 25, 1960	5
Elgin	IL	713.0	713.11 ft, Jul 24, 2017	0
Fox Lake	IL	6.0	8.12 ft, Apr 5, 1960	6
Lake Villa	IL	6.0	8.90 ft, Jul 4, 1938	7
McHenry (Stratton Lock and Dam) tailwater	IL	4.0	9.00 ft, Jul 5, 1938	6
Montgomery	IL	13.5	16.50 ft, Jul 18, 1996	1
Rochester	WI	6.0	6.29 ft, Apr 21, 2026	0
South Elgin Dam	IL	14.5	15.04 ft, Apr 18, 2013	0
Waukesha	WI	6.0	8.85 ft, Jun 9, 2008	0
Yorkville (Palmer Dam)	IL	15.5	21.00 ft, Jul 18, 1996	1
Antioch	IL	6.0	8.34 ft, Apr 5, 1960	6
Johnsburg this gauge	IL	6.5	8.90 ft, Jul 4, 1938	2
New Munster	WI	11.0	17.47 ft, Jul 13, 2017	5

Other gauges in McHenry County

Flood gauges in McHenry County

Mchenry	7.0	7.48 ft, Jun 26, 2013	0
Algonquin	3.0	4.50 ft, Apr 1, 1916	12
Algonquin tailwater	9.5	14.00 ft, Jul 5, 1938	6
McHenry (Stratton Lock and Dam) tailwater	4.0	9.00 ft, Jul 5, 1938	6
Marengo	12.0	13.06 ft, Sep 4, 2018	0
Wonder Lake	9.0	14.30 ft, Jun 11, 1967	1
Spring Grove	11.0	14.26 ft, Sep 26, 1986	0

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

NOAA National Water Prediction Service, gauge JHNI2, 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.