Mesotrophic Lakes in Illinois

19 mesotrophic lakes in Illinois. Moderate nutrients, good water quality.

Most well-managed working lakes register as mesotrophic — the band that balances productivity with clarity. 19 lakes in Illinois sit in the mesotrophic band. About 0% are deep (50+ ft); the rest are shallower basins where watershed management keeps nutrients from pushing the system into eutrophy.

Mesotrophic lakes tend to grade B or C on the LakeGrade rubric — the productive-but-clear band lines up with the middle of the letter grades.

#	Lake	County	Grade	Clarity	Depth	TSI
1	Powderhorn Lake	Cook	A	10.1 ft	-	42
2	Baumann Park Lake	Winnebago	A	10.2 ft	-	42
3	Silver Lake	McHenry	B	7 ft	-	44
4	Silver Lake	McHenry	B	10 ft	-	44
5	Timber Lake	Lake	B	10.6 ft	-	43
6	Boulder South Lake	Perry	B	8.8 ft	-	44
7	Wampum Lake	Cook	B	6.9 ft	-	47
8	Timber Lake	Carroll	B	11.5 ft	-	42
9	Round Lake	Lake	B	7.4 ft	-	48
10	Big Rock Lake	Kane	B	8.1 ft	-	42
11	Kinkaid Lake	Jackson	B	-	-	50
12	Lake Calumet	Cook	B	-	-	47
13	Flatfoot Lake	Cook	B	6.3 ft	-	44
14	Glendale Lake	Pope	B	4.8 ft	-	49
15	Calumet Lake	Cook	B	4.3 ft	-	47
16	Icebox Quarry Lake	Cook	C	9 ft	-	45
17	Forge Quarry Lake	Cook	C	8.5 ft	-	46
18	Bass Lake	Lee	C	8.1 ft	-	47
19	Woodhaven Lake	Lee	C	6.7 ft	-	50

All mesotrophic lakes →Minnesota version →Wisconsin version →Michigan version →Iowa version →Ohio version →Pennsylvania version →New York version →Missouri version →Indiana version →North Dakota version →South Dakota version →All Illinois lakes →

Source: EPA National Aquatic Resource Surveys, 2026.