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

Keweenaw County Lake Quality

Michigan, 51 lakes, average grade B (Good)

Keweenaw County has 51 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. 11 of those lakes carry an A–F grade. The county-level summary describes that subset, not every water body listed. With an average grade of B, Keweenaw County sits comfortably above the Michigan median.

The county's lakes lean shallow, which makes the grades sensitive to wind, sediment-resuspension, and any nutrient inputs from the watershed. The cleanest lake on the books is Lake Ahmik (B); the most-stressed is Chickenbone Lake (C).

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Top-rated places to stay near Keweenaw County

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Quick Answers for Keweenaw County

Cleanest lakes in Keweenaw County →Cleanest lakes in Michigan →Safest swimming lakes in Michigan →

Planning a trip? Check special fishing regulations for Lake Ahmik, whether the fish are safe to eat, and the best times to fish — or check the official Michigan fishing regulations.

Fishing in Keweenaw County

Keweenaw County Fishing Guide

Fish species and best-graded lakes in Keweenaw County

All Lakes in Keweenaw County

51 lakes · 11 graded, 40 not rated11 graded lakes · 40 not rated, hidden

Include not-rated lakes (40)

#	Lake	Grade	Clarity	Phosphorus	Algae	Trophic	Max Depth	Access
1	BLake AhmikKeweenaw	B	6.6 ft	15.2 µg/L	No recent samples	No recent samples	No recent samples	Not recorded
2	BGratiot LakeKeweenaw	B	17 ft	9 µg/L	No recent samples	No recent samples	70 ft	Not recorded
3	BSargent LakeKeweenaw	B	10.5 ft	13.2 µg/L	No recent samples	No recent samples	No recent samples	Not recorded
4	BLake RichieKeweenaw	B	9.2 ft	16.1 µg/L	No recent samples	No recent samples	No recent samples	Not recorded
5	BLake HarveyKeweenaw	B	10.4 ft	12.2 µg/L	No recent samples	No recent samples	No recent samples	Not recorded
6	BBeaver LakeKeweenaw	B	8.9 ft	12.9 µg/L	No recent samples	No recent samples	No recent samples	Not recorded
7	BFeldtmann LakeKeweenaw	B	7.5 ft	11.5 µg/L	No recent samples	No recent samples	No recent samples	Not recorded
8	BLake DesorKeweenaw	B	7.2 ft	11.7 µg/L	No recent samples	No recent samples	No recent samples	Not recorded
9	BLake GeorgeKeweenaw	B	8 ft	9.9 µg/L	No recent samples	No recent samples	No recent samples	Not recorded
10	BSiskiwit LakeKeweenaw	B	20.5 ft	4.4 µg/L	No recent samples	No recent samples	No recent samples	Not recorded
11	CChickenbone LakeKeweenaw	C	6.1 ft	28.2 µg/L	No recent samples	No recent samples	No recent samples	Not recorded
	NRLake GratiotKeweenaw	NR	16.5 ft	No recent samples	No recent samples	No recent samples	70 ft	✓ Public
	NRWallace LakeKeweenaw	NR	No recent samples	No recent samples	No recent samples	No recent samples	No recent samples	Not recorded
	NRLake WhittleseyKeweenaw	NR	11.6 ft	23.3 µg/L	No recent samples	No recent samples	No recent samples	Not recorded
	NRHidden LakeKeweenaw	NR	2.5 ft	27.5 µg/L	No recent samples	No recent samples	No recent samples	Not recorded
	NREpidote LakeKeweenaw	NR	7.2 ft	No recent samples	No recent samples	No recent samples	No recent samples	Not recorded
	NRAngleworm LakeKeweenaw	NR	No recent samples	No recent samples	No recent samples	No recent samples	No recent samples	Not recorded
	NRLake BensonKeweenaw	NR	No recent samples	No recent samples	No recent samples	No recent samples	No recent samples	Not recorded
	NROtter LakeKeweenaw	NR	No recent samples	No recent samples	No recent samples	No recent samples	No recent samples	Not recorded
	NRLake LivermoreKeweenaw	NR	No recent samples	No recent samples	No recent samples	No recent samples	No recent samples	Not recorded
	NRLeSage LakeKeweenaw	NR	No recent samples	No recent samples	No recent samples	No recent samples	No recent samples	Not recorded
	NRLake MasonKeweenaw	NR	No recent samples	No recent samples	No recent samples	No recent samples	No recent samples	Not recorded
	NRIntermediate LakeKeweenaw	NR	No recent samples	No recent samples	No recent samples	No recent samples	No recent samples	Not recorded
	NRHatchet LakeKeweenaw	NR	No recent samples	No recent samples	No recent samples	No recent samples	No recent samples	Not recorded
	NRWood LakeKeweenaw	NR	No recent samples	No recent samples	No recent samples	No recent samples	No recent samples	Not recorded
	NRMud LakeKeweenaw	NR	No recent samples	No recent samples	No recent samples	No recent samples	No recent samples	Not recorded
	NRLake HalloranKeweenaw	NR	No recent samples	No recent samples	No recent samples	No recent samples	No recent samples	Not recorded
	NRLake Fanny HooeKeweenaw	NR	No recent samples	No recent samples	No recent samples	No recent samples	40 ft	✓ Public
	NRLake BaileyKeweenaw	NR	No recent samples	No recent samples	No recent samples	No recent samples	9 ft	Not recorded
	NRLake ManganeseKeweenaw	NR	No recent samples	No recent samples	No recent samples	No recent samples	30 ft	Not recorded
	NRLake MedoraKeweenaw	NR	No recent samples	No recent samples	No recent samples	No recent samples	30 ft	✓ Public
	NRMeadow LakeKeweenaw	NR	No recent samples	No recent samples	No recent samples	No recent samples	25 ft	Not recorded
	NRSchlatter LakeKeweenaw	NR	No recent samples	No recent samples	No recent samples	No recent samples	24 ft	Not recorded
	NRBreakfast LakeKeweenaw	NR	No recent samples	No recent samples	No recent samples	No recent samples	34 ft	Not recorded
	NRLake AddieKeweenaw	NR	No recent samples	No recent samples	No recent samples	No recent samples	22 ft	Not recorded
	NRHoar LakeKeweenaw	NR	No recent samples	No recent samples	No recent samples	No recent samples	27 ft	Not recorded
	NRLa Belle, LacKeweenaw	NR	No recent samples	No recent samples	No recent samples	No recent samples	35 ft	✓ Public
	NRDeer LakeKeweenaw	NR	No recent samples	No recent samples	No recent samples	No recent samples	16 ft	Not recorded
	NRThayer LakeKeweenaw	NR	No recent samples	No recent samples	No recent samples	No recent samples	5 ft	✓ Public
	NRLake ShesheebKeweenaw	NR	No recent samples	No recent samples	No recent samples	No recent samples	No recent samples	Not recorded
	NRLinklater LakeKeweenaw	NR	No recent samples	No recent samples	No recent samples	No recent samples	No recent samples	Not recorded
	NRLake EvaKeweenaw	NR	No recent samples	No recent samples	No recent samples	No recent samples	No recent samples	Not recorded
	NRMcDonald LakeKeweenaw	NR	No recent samples	No recent samples	No recent samples	No recent samples	No recent samples	Not recorded
	NRAmygdaloid LakeKeweenaw	NR	No recent samples	No recent samples	No recent samples	No recent samples	No recent samples	Not recorded
	NRPatterson LakeKeweenaw	NR	No recent samples	No recent samples	No recent samples	No recent samples	No recent samples	Not recorded
	NRLake OjibwayKeweenaw	NR	No recent samples	No recent samples	No recent samples	No recent samples	No recent samples	Not recorded
	NRCopper Falls LakeKeweenaw	NR	No recent samples	No recent samples	No recent samples	No recent samples	No recent samples	Not recorded
	NRLake BaileyKeweenaw	NR	No recent samples	No recent samples	No recent samples	No recent samples	No recent samples	Not recorded
	NRMud LakeKeweenaw	NR	No recent samples	No recent samples	No recent samples	No recent samples	No recent samples	Not recorded
	NRLily LakeKeweenaw	NR	No recent samples	No recent samples	No recent samples	No recent samples	No recent samples	Not recorded
	NRPerch LakeKeweenaw	NR	No recent samples	No recent samples	No recent samples	No recent samples	No recent samples	Not recorded

NR = not rated: there is not enough recent sampling to support a letter. That is EPA Integrated Reporting Category 3 (insufficient information), not a failing grade. How grading works.

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Other Counties in Michigan

Dickinson County

43 lakes · Avg grade A

Clare County

47 lakes · Avg grade A

Ogemaw County

50 lakes · Avg grade A

Cheboygan County

31 lakes · Avg grade A

Roscommon County

26 lakes · Avg grade A

Gladwin County

29 lakes · Avg grade A

See how Keweenaw County stacks up in the national county water-quality rankings, or browse the full directory of graded lakes across all United States (49 states), Canada (Ontario, Québec, Nova Scotia, British Columbia and Newfoundland and Labrador), and 38 other country hubs..

Source: EPA National Aquatic Resource Surveys, 2026.