Lake County Lake Quality

Illinois, 16 lakes, average grade C (Fair)

There are 16 graded lakes in Lake County. The mix is varied enough that the county-level average tells you the broad strokes, not the choose-this-cabin specifics. Lake County averages to a C. The distribution behind that average matters more than the letter: a few stressed lakes versus many decent ones can produce the same average as the inverse.

Most of the county's monitored lakes are shallow — under 50 feet — which means wind keeps the water column mixed all summer and sediment-bound phosphorus releases back into the surface layer whenever the bottom is disturbed. Loch Lomond Lake (A) is the cleanest in the county.

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Quick Answers for Lake County

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

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

All Lakes in Lake County

Rank	Lake	Grade	Clarity	Phosphorus
1	Loch Lomond Lake	A	16.5 ft	-
2	Timber Lake	B	10.6 ft	-
3	Round Lake	B	7.4 ft	19.5 µg/L
4	Grays Lake	B	3.5 ft	18 µg/L
5	Catherine Lake	B	7.4 ft	27.5 µg/L
6	Channel Lake	C	8 ft	34.5 µg/L
7	Long Lake	D	3.4 ft	35 µg/L
8	Hastings Lake	D	3.4 ft	-
9	Grass Lake	D	1.4 ft	57.5 µg/L
10	Long Lake	D	2.9 ft	41.5 µg/L
11	Fox Lake	D	1.9 ft	43 µg/L
12	Petite Lake	D	2.5 ft	36 µg/L
13	Nippersink Lake	D	1.3 ft	44.5 µg/L
14	Marie Lake	D	2.7 ft	69 µg/L
15	Bluff Lake	D	4 ft	315.5 µg/L