Late afternoon sun over Slim Lake, scattering a bright path across wind-textured water

Lake County Lake Quality

Illinois, 65 lakes, measured by Illinois EPA

Lake County has 65 monitored lakes, enough that within-county variation matters as much as the county average. Some are deep glacial basins, others are shallow agricultural-watershed waters, and the measurements reflect that mix. 19 of those lakes carry recent nutrient and algae readings. The county-level summary describes that subset, not every water body listed. The county's readings sit in the middle of the Illinois range, with one or two lakes pulling the average up or down depending on year.

The county's lakes lean shallow, which makes the readings sensitive to wind, sediment-resuspension, and any nutrient inputs from the watershed. The cleanest measured lake is Grays Lake.

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Quick Answers for Lake County

Cleanest lakes in Lake County →Cleanest lakes in Illinois →Best swimming lakes in Illinois →

Planning a trip? Check special fishing regulations for Grays Lake — or check the official Illinois fishing regulations.

All Lakes in Lake County

65 lakes · 19 ranked on readings, 46 without enough sampling19 lakes ranked on readings · 46 without enough sampling, hidden

Include not-rated lakes (46)

#	Lake	Clarity	Phosphorus	Algae	Trophic	Max Depth	Access
1	Grays LakeLake	3.5 ft	23 µg/L	3.1 µg/L	No recent samples	No recent samples	Not recorded
2	Catherine LakeLake	7.4 ft	30 µg/L	4.9 µg/L	No recent samples	No recent samples	✓ Public
3	Cedar LakeLake	No recent samples	No recent samples	4.7 µg/L	No recent samples	No recent samples	Not recorded
4	Deep LakeLake	No recent samples	No recent samples	2.2 µg/L	No recent samples	No recent samples	Not recorded
5	Round LakeLake	7.4 ft	20.5 µg/L	7.1 µg/L	No recent samples	No recent samples	✓ Public
6	Channel LakeLake	8 ft	36 µg/L	9.5 µg/L	No recent samples	No recent samples	✓ Public
7	Zurich LakeLake	No recent samples	No recent samples	7.9 µg/L	No recent samples	No recent samples	Not recorded
8	West Loon LakeLake	No recent samples	No recent samples	9.3 µg/L	No recent samples	No recent samples	Not recorded
9	Tower LakeLake	No recent samples	No recent samples	18.3 µg/L	No recent samples	No recent samples	Not recorded
10	East Loon LakeLake	No recent samples	No recent samples	15.9 µg/L	No recent samples	No recent samples	Not recorded
11	Fox LakeLake	1.9 ft	72 µg/L	28.2 µg/L	No recent samples	No recent samples	Not recorded
12	Long LakeLake	3.4 ft	81 µg/L	57.1 µg/L	No recent samples	No recent samples	✓ Public
13	Grass LakeLake	1.4 ft	103.5 µg/L	37.1 µg/L	No recent samples	No recent samples	✓ Public
14	Marie LakeLake	2.7 ft	76 µg/L	55 µg/L	No recent samples	No recent samples	Not recorded
15	Nippersink LakeLake	1.3 ft	88 µg/L	36.6 µg/L	No recent samples	No recent samples	✓ Public
16	Diamond LakeLake	No recent samples	No recent samples	63.6 µg/L	No recent samples	No recent samples	✓ Public
17	Valley LakeLake	No recent samples	No recent samples	50.7 µg/L	No recent samples	No recent samples	Not recorded
18	Louise LakeLake	No recent samples	No recent samples	80.2 µg/L	No recent samples	No recent samples	Not recorded
19	Slocum LakeLake	No recent samples	No recent samples	90.3 µg/L	No recent samples	No recent samples	Not recorded
	Loch Lomond LakeLake	16.5 ft	No recent samples	No recent samples	No recent samples	No recent samples	✓ Public
	Hastings LakeLake	3.4 ft	No recent samples	No recent samples	No recent samples	No recent samples	Not recorded
	Timber LakeLake	10.6 ft	No recent samples	No recent samples	No recent samples	No recent samples	✓ Public
	Petite LakeLake	2.5 ft	70 µg/L	59 µg/L	No recent samples	No recent samples	Not recorded
	Bluff LakeLake	4 ft	315.5 µg/L	30.8 µg/L	No recent samples	No recent samples	✓ Public
	Sterling LakeLake	No recent samples	No recent samples	No recent samples	No recent samples	27 ft	✓ Public
	Minear LakeLake	No recent samples	No recent samples	No recent samples	No recent samples	22 ft	Not recorded
	Liberty LakeLake	No recent samples	No recent samples	No recent samples	No recent samples	14 ft	Not recorded
	Lake CharlesLake	No recent samples	No recent samples	No recent samples	No recent samples	10.9 ft	Not recorded
	Saint Marys LakeLake	No recent samples	No recent samples	No recent samples	No recent samples	18 ft	Not recorded
	Gages LakeLake	No recent samples	No recent samples	No recent samples	No recent samples	55 ft	Not recorded
	Third LakeLake	No recent samples	No recent samples	No recent samples	No recent samples	70 ft	Not recorded
	Druce LakeLake	No recent samples	No recent samples	No recent samples	No recent samples	32.5 ft	Not recorded
	Highland LakeLake	No recent samples	No recent samples	No recent samples	No recent samples	30 ft	Not recorded
	Countryside LakeLake	No recent samples	No recent samples	No recent samples	No recent samples	10 ft	Not recorded
	Sylvan LakeLake	No recent samples	No recent samples	No recent samples	No recent samples	7.5 ft	Not recorded
	Davis LakeLake	No recent samples	No recent samples	No recent samples	No recent samples	18.1 ft	Not recorded
	Lake ShereeLake	No recent samples	No recent samples	No recent samples	No recent samples	5 ft	Not recorded
	Bangs LakeLake	No recent samples	No recent samples	No recent samples	No recent samples	32 ft	✓ Public
	Wooster LakeLake	No recent samples	No recent samples	No recent samples	No recent samples	29 ft	Not recorded
	Duck LakeLake	No recent samples	No recent samples	No recent samples	No recent samples	9 ft	Not recorded
	Redhead LakeLake	No recent samples	No recent samples	No recent samples	No recent samples	4.5 ft	Not recorded
	Brandenburg LakeLake	No recent samples	No recent samples	No recent samples	No recent samples	15 ft	Not recorded
	Fish LakeLake	No recent samples	No recent samples	No recent samples	No recent samples	17 ft	Not recorded
	Sullivan LakeLake	No recent samples	No recent samples	No recent samples	No recent samples	10.5 ft	Not recorded
	Grassy LakeLake	No recent samples	No recent samples	No recent samples	No recent samples	8.5 ft	Not recorded
	Lake BarringtonLake	No recent samples	No recent samples	No recent samples	No recent samples	13 ft	Not recorded
	Honey LakeLake	No recent samples	No recent samples	No recent samples	No recent samples	18 ft	Not recorded
	Forest LakeLake	No recent samples	No recent samples	No recent samples	No recent samples	9 ft	Not recorded
	Turner LakeLake	No recent samples	No recent samples	No recent samples	No recent samples	10 ft	✓ Public
	Dunns LakeLake	No recent samples	No recent samples	No recent samples	No recent samples	7.5 ft	Not recorded
	Spring LakeLake	No recent samples	No recent samples	No recent samples	No recent samples	20 ft	✓ Public
	Antioch LakeLake	No recent samples	No recent samples	No recent samples	No recent samples	9 ft	Not recorded
	Crooked LakeLake	No recent samples	No recent samples	No recent samples	No recent samples	26.5 ft	Not recorded
	Sand LakeLake	No recent samples	No recent samples	No recent samples	No recent samples	32 ft	Not recorded
	Slough LakeLake	No recent samples	No recent samples	No recent samples	No recent samples	19 ft	Not recorded
	Miltmore LakeLake	No recent samples	No recent samples	No recent samples	No recent samples	21 ft	Not recorded
	Fourth LakeLake	No recent samples	No recent samples	No recent samples	No recent samples	5.5 ft	Not recorded
	Lake LindenLake	No recent samples	No recent samples	No recent samples	No recent samples	11 ft	Not recorded
	Waterford LakeLake	No recent samples	No recent samples	No recent samples	No recent samples	13 ft	Not recorded
	Elmwood Farms LakeLake	No recent samples	No recent samples	No recent samples	No recent samples	11 ft	Not recorded
	Huntley LakeLake	No recent samples	No recent samples	No recent samples	No recent samples	36 ft	Not recorded
	White LakeLake	No recent samples	No recent samples	No recent samples	No recent samples	9 ft	Not recorded
	Silver LakeLake	No recent samples	No recent samples	No recent samples	No recent samples	22.5 ft	Not recorded
	Redwing Slough LakeLake	No recent samples	No recent samples	No recent samples	No recent samples	4 ft	Not recorded
	Deer LakeLake	No recent samples	No recent samples	No recent samples	No recent samples	8 ft	Not recorded

NR = no nutrient or algae reading on record. The measurements are published as the authority reports them. Where the data comes from.

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Browse every Illinois lake, or the full directory of lakes across all United States (49 states), Canada (Ontario, Québec, Nova Scotia, British Columbia and Newfoundland and Labrador), and 38 other country hubs..

Source: the Illinois Environmental Protection Agency. See data sources.