What are oligotrophic lakes in Wisconsin?

127 oligotrophic lakes in Wisconsin. Low nutrients, clear water, excellent for swimming.

What does oligotrophic mean?

Low nutrients, clear water, excellent for swimming.

Oligotrophic Lakes in Wisconsin

Oligotrophic lakes are the clear, cold, nutrient-poor end of the trophic scale. The Carlson Trophic State Index measures this as TSI below 40 — water transparent enough to see 15+ feet down, total phosphorus under 12 µg/L, chlorophyll-a barely registering. Across Wisconsin, 127 lakes register as oligotrophic — 39% of them break 50 feet of depth, which is the structural condition that underwrites the trophic class. Without depth and a low-nutrient watershed, oligotrophy is hard to sustain.

Oligotrophic lakes almost always carry the lowest phosphorus and chlorophyll-a readings on record, since the same low-nutrient conditions produce both the trophic class and the clear water.

#	Lake	County	Clarity	Depth	TSI
1	Geneva Lake	Walworth	21 ft	135 ft	37
2	Whitefish Lake	Sawyer	13.5 ft	105 ft	39
3	Round Lake	Sawyer	21.1 ft	74 ft	35
4	Blueberry Lake	Sawyer	14.8 ft	29 ft	40
5	Little Round Lake	Sawyer	17.3 ft	38 ft	36
6	Osprey Lake	Sawyer	16 ft	32 ft	38
7	Grindstone Lake	Sawyer	17.4 ft	60 ft	38
8	Oneida Lake	Outagamie	-	-	39
9	Mission Lake	Shawano	17.5 ft	44 ft	40
10	King Lake	Marinette	-	70 ft	32
11	Bug Lake	Forest	-	-	34
12	Cloud Lake	Forest	-	25 ft	37
13	Plum Lake	Vilas	14.2 ft	57 ft	40
14	Whitefish Lake	Douglas	25 ft	102 ft	35
15	Round Lake	Oconto	16.8 ft	31 ft	39
16	Deep Lake	Adams	15.5 ft	49 ft	39
17	Beasley Lake	Waupaca	18.4 ft	47 ft	39
18	Bass Lake	Washburn	16 ft	31 ft	39
19	Bass Lake	Oconto	16.8 ft	40 ft	37
20	Clear Lake	Sawyer	17.3 ft	32 ft	38
21	Clear Lake	Rusk	13.7 ft	74 ft	40
22	Clear Lake	Polk	15.5 ft	26 ft	40
23	Clear Lake	Lincoln	18 ft	45 ft	37
24	Clear Lake	Oneida	-	95 ft	38
25	Explosion Lake	Oconto	17 ft	10 ft	39
26	Sugar Camp Lake	Oneida	16.5 ft	-	37
27	Little Spider Lake	Vilas	16 ft	23 ft	38
28	Marl Lake	Waupaca	13.6 ft	59 ft	39
29	Rosalind Lake	Vilas	19.3 ft	-	36
30	Lake Lucerne	Forest	18.7 ft	73 ft	36
31	Long Lake	Bayfield	16.2 ft	28 ft	39
32	Long Lake	Burnett	21.5 ft	41 ft	36
33	Long Lake	Waushara	14.5 ft	71 ft	39
34	Long Lake	Lincoln	14.5 ft	64 ft	40
35	Lake Metonga	Forest	22 ft	79 ft	37
36	Anderson Lake	Vilas	20.5 ft	63 ft	36
37	Archibald Lake	Oconto	17.8 ft	50 ft	37
38	Carlin Lake	Vilas	21 ft	36 ft	33
39	Wolf Lake	Adams	15 ft	58 ft	39
40	Butternut Lake	Forest	19.5 ft	42 ft	37
41	Stone Lake	Washburn	23 ft	49 ft	35
42	Paya Lake	Oconto	20 ft	40 ft	37
43	Samoset Lake	Bayfield	15 ft	40 ft	40
44	North Twin Lake	Polk	-	27 ft	37
45	Papoose Lake	Vilas	15 ft	65 ft	38
46	Boot Lake	Oconto	21.5 ft	38 ft	36
47	Eagle Lake	Bayfield	17 ft	52 ft	40
48	Little Hills Lake	Waushara	14 ft	20 ft	40
49	White Lake	Marquette	17 ft	60 ft	37
50	Upper Kaubashine Lake	Oneida	19 ft	56 ft	37
51	Squash Lake	Oneida	17.5 ft	74 ft	37
52	Plummer Lake	Vilas	18 ft	85 ft	38
53	Thunder Lake	Marinette	18 ft	62 ft	37
54	Star Lake	Oconto	17 ft	21 ft	39
55	Diamond Lake	Bayfield	13 ft	83 ft	40
56	Alva Lake	Oneida	19.5 ft	43 ft	37
57	Franklin Lake	Forest	16 ft	46 ft	38
58	Franklin Lake	Oneida	16.2 ft	25 ft	39
59	Charnley Lake	Iron	13.5 ft	-	39
60	Cable Lake	Bayfield	15.5 ft	-	40
61	Big Portage Lake	Vilas	18.5 ft	40 ft	38
62	Crystal Lake	Marquette	16.8 ft	60 ft	38
63	Crystal Lake	Sheboygan	20 ft	-	37
64	Rinehart Lake	Portage	19 ft	27 ft	38
65	Perch Lake	Langlade	17.3 ft	21 ft	39
66	Mildred Lake	Oneida	18 ft	45 ft	38
67	Half Moon Lake	Polk	15.3 ft	60 ft	40
68	Manson Lake	Oneida	12 ft	54 ft	40
69	Forest Lake	Vilas	22.2 ft	60 ft	37
70	Pearl Lake	Waushara	19 ft	45 ft	37
71	Fish Lake	Burnett	14 ft	-	40
72	Wood Lake	Marquette	14 ft	53 ft	39
73	Sea Lion Lake	Florence	21 ft	82 ft	36
74	Lower Kaubashine Lake	Oneida	13.8 ft	36 ft	39
75	Upper Eau Claire Lake	Bayfield	18.7 ft	92 ft	37
76	Hasbrook Lake	Oneida	21 ft	50 ft	36
77	Sunset Lake	Vilas	17.3 ft	30 ft	38
78	Black Oak Lake	Vilas	29 ft	85 ft	33
79	Flannery Lake	Oneida	14.5 ft	35 ft	40
80	Clark Lake	Door	12.5 ft	25 ft	39
81	Fishtrap Lake	Vilas	12.2 ft	34 ft	40
82	Lynx Lake	Vilas	12.8 ft	20 ft	39
83	Seven Island Lake	Lincoln	14 ft	31 ft	38
84	Tozer Lake	Washburn	16 ft	53 ft	39
85	Pine Lake	Waukesha	25 ft	85 ft	35
86	Bear Paw Lake	Oconto	16 ft	20 ft	38
87	Presque Isle Lake	Vilas	18 ft	103 ft	37
88	Leader Lake	Douglas	15.3 ft	56 ft	38
89	Keyes Lake	Florence	21 ft	-	36
90	Blue Lake	Oneida	23 ft	49 ft	35
91	Lee Lake	Oneida	22.5 ft	44 ft	34
92	Dutch Hollow Lake	Sauk	15 ft	38 ft	40
93	Hammil Lake	Bayfield	14.6 ft	47 ft	39
94	Middle Kimball Lake	Washburn	16 ft	77 ft	39
95	Two Sisters Lake	Oneida	19.6 ft	-	36
96	Crawling Stone Lake	Vilas	16 ft	87 ft	38
97	Clearwater Lake	Oneida	16.8 ft	48 ft	37
98	Middle Eau Claire Lake	Bayfield	18.2 ft	66 ft	38
99	Gilas Lake	Marinette	15 ft	88 ft	39
100	South Twin Lake	Washburn	14 ft	29 ft	39

All oligotrophic lakes →Minnesota version →Illinois version →Michigan version →Iowa version →Ohio version →Pennsylvania version →New York version →Missouri version →Indiana version →North Dakota version →South Dakota version →Florida version →Colorado version →North Carolina version →Vermont version →Texas version →Oregon version →Arkansas version →Oklahoma version →Kansas version →Nebraska version →Nevada version →Arizona version →Idaho version →Montana version →New Mexico version →Tennessee version →Alabama version →Virginia version →Kentucky version →Utah version →Washington version →Wyoming version →Georgia version →Massachusetts version →Ontario version →Québec version →Nova Scotia version →British Columbia version →Newfoundland and Labrador version →All Wisconsin lakes →

Source: EPA National Aquatic Resource Surveys, 2026.