Deep Lakes in Minnesota & Wisconsin

Q: Why are deep lakes important for water quality?

Deep lakes maintain a thermocline (temperature barrier) that keeps bottom water cold and oxygen-rich throughout summer. This supports coldwater fish species like lake trout and cisco that cannot survive in shallower, warmer lakes. Deep lakes also resist algae blooms better because their large volume dilutes nutrients.

Q: What is the deepest lake in Minnesota and Wisconsin?

The deepest lakes in both states exceed 200 feet. These deep lakes are typically located in geologically carved basins from glacial activity and offer some of the best water quality and coldwater fishing in the region.

Lakes over 50 feet deep in Minnesota and Wisconsin. Deep lakes maintain cold, oxygenated water below the thermocline year-round, supporting coldwater species like lake trout, cisco, and whitefish.

Deep (50+ ft)Medium (20-50 ft)Shallow (<20 ft)

100

Total Lakes

Minnesota

Wisconsin

Rank	Lake	County	State	Grade	Depth	Area	Fish
1	Gilbert Pit Lake	St. Louis	MN	B	443 ft	243.41 acres	10
2	St James Pit Lake	St. Louis	MN	A	381 ft	124.18 acres	5
3	Wazee Lake	Jackson	WI	A	350 ft	146 acres	0
4	Iron Chief Complex Lake	St. Louis	MN	A	262.1 ft	207.44 acres	3
5	Green Lake	Green Lake	WI	B	236 ft	7.9K acres	7
6	Green Lake	Green Lake	WI	B	236 ft	7.9K acres	7
7	Green Lake	Green Lake	WI	C	236 ft	7.9K acres	7
8	Green Lake	Green Lake	WI	B	236 ft	7.9K acres	7
9	Green Lake East Basin	Green Lake	WI	B	236 ft	7.9K acres	7
10	Silver Creek Estuary Lake	Green Lake	WI	F	236 ft	7.9K acres	7
11	City Millpond	Green Lake	WI	C	236 ft	7.9K acres	7
12	Lasalle Lake	Hubbard	MN	B	213 ft	237.9 acres	15
13	Watap Lake	Cook	MN	C	210 ft	2.0K acres	1
14	Gabimichigami Lake	Cook	MN	B	209 ft	1.2K acres	0
15	Ten Mile Lake	Cass	MN	A	208 ft	5.1K acres	17
16	Loon Lake	Cook	MN	A	202 ft	1.1K acres	10
17	Gunflint Lake	Cook	MN	A	200 ft	4.0K acres	12
18	Little Gunflint Lake	Cook	MN	A	200 ft	4.0K acres	12
19	Strup Lake	Lake	MN	C	195 ft	1.7K acres	5
20	Sand Point Lake	St. Louis	MN	C	184 ft	8.5K acres	21
21	Sand Point Lake	St. Louis	MN	D	184 ft	8.5K acres	21
22	Sand Point Lake	St. Louis	MN	D	184 ft	8.5K acres	21
23	Larson Lake	Itasca	MN	A	177 ft	208.18 acres	6
24	Lac la Croix Lake	St. Louis	MN	C	168 ft	29.6K acres	12
25	Crooked Lake	Lake	MN	C	165 ft	10.4K acres	0
26	Carlos Lake	Douglas	MN	A	163 ft	2.6K acres	21
27	Alvin Lake	Douglas	MN	B	163 ft	2.6K acres	21
28	Rainy Lake	Koochiching	MN	D	161 ft	210.2K acres	17
29	Rainy Lake	St. Louis	MN	D	161 ft	210.2K acres	17
30	Rainy Lake	St. Louis	MN	C	161 ft	210.2K acres	17
31	Rainy Lake	St. Louis	MN	C	161 ft	210.2K acres	17
32	Rainy Lake	Koochiching	MN	D	161 ft	210.2K acres	17
33	Rainy Lake	Koochiching	MN	D	161 ft	210.2K acres	17
34	Rainy Lake	Koochiching	MN	D	161 ft	210.2K acres	17
35	Rainy Lake	Koochiching	MN	D	161 ft	210.2K acres	17
36	Rainy Lake	Koochiching	MN	C	161 ft	210.2K acres	17
37	Trout Lake	Itasca	MN	A	157 ft	1.7K acres	9
38	Caribou Lake	Itasca	MN	A	152 ft	246.5 acres	7
39	Namakan Lake	St. Louis	MN	C	150 ft	24.1K acres	18
40	Namakan Lake	St. Louis	MN	C	150 ft	24.1K acres	18
41	Namakan Lake	St. Louis	MN	D	150 ft	24.1K acres	18
42	Little Saganaga Lake	Cook	MN	C	150 ft	1.6K acres	5
43	Namakan Lake	St. Louis	MN	B	150 ft	24.1K acres	18
44	Snowbank Lake	Lake	MN	B	150 ft	4.7K acres	11
45	Steamboat Bay Lake	Cass	MN	B	150 ft	103.4K acres	18
46	Kabekona Bay Lake	Cass	MN	A	150 ft	103.4K acres	18
47	16-0524-00 Lake	Cook	MN	A	142 ft	837.01 acres	4
48	Six Lake	Otter Tail	MN	A	140 ft	196.53 acres	11
49	Elmo Lake	Washington	MN	B	140 ft	256.82 acres	13
50	South Lake	Cook	MN	C	140 ft	1.1K acres	6
51	Whitefish Lake	Crow Wing	MN	A	138 ft	7.7K acres	23
52	Rose Lake	Otter Tail	MN	A	137 ft	1.2K acres	17
53	Long Lake	Hubbard	MN	A	135 ft	1.9K acres	14
54	Trout Lake	Itasca	MN	A	135 ft	1.9K acres	15
55	Big Sand Lake	Hubbard	MN	A	135 ft	1.6K acres	16
56	Geneva Lake	Walworth	WI	A	135 ft	5.4K acres	6
57	Geneva Lake	Walworth	WI	A	135 ft	5.4K acres	6
58	Geneva Lake Site B	Walworth	WI	A	135 ft	5.4K acres	6
59	Outlet To Lake Geneva	Walworth	WI	F	135 ft	5.4K acres	6
60	Kabekona Lake	Hubbard	MN	A	133 ft	2.4K acres	20
61	Koronis Lake	Stearns	MN	C	132 ft	3.0K acres	22
62	Rose Lake	Cook	MN	B	130 ft	476.95 acres	5
63	Duncan Lake	Cook	MN	A	130 ft	476.95 acres	5
64	Kekekabic Lake	Lake	MN	A	130 ft	54.91 acres	0
65	Kek Lake	Lake	MN	A	130 ft	54.91 acres	0
66	Oyster Lake	St. Louis	MN	C	130 ft	762.91 acres	0
67	Mountain Lake	Unknown	MN	A	130 ft	1.3K acres	7
68	Rove Lake	Cook	MN	C	130 ft	1.3K acres	7
69	Roosevelt Lake	Cass	MN	A	129 ft	1.5K acres	18
70	Long Lake	Otter Tail	MN	A	128 ft	1.3K acres	16
71	Big Trout Lake	Crow Wing	MN	A	128 ft	1.4K acres	20
72	Burntside Lake	St. Louis	MN	A	126 ft	7.3K acres	15
73	Round Lake	Aitkin	MN	A	125 ft	736.65 acres	18
74	Jasper Lake	Cook	MN	B	125 ft	245.78 acres	0
75	Mina Lake	Douglas	MN	A	123 ft	411.41 acres	18
76	Big Watab Lake	Stearns	MN	A	123 ft	245.56 acres	15
77	Deer Lake	Itasca	MN	A	121 ft	4.1K acres	17
78	Bluewater Lake	Itasca	MN	A	120 ft	364.22 acres	15
79	Otter Tail Lake	Otter Tail	MN	A	120 ft	14.1K acres	17
80	White Earth Lake	Becker	MN	A	120 ft	2.0K acres	17
81	Becker Lake	Becker	MN	D	120 ft	2.0K acres	17
82	Peter Lake	Cook	MN	A	120 ft	281.98 acres	4
83	Drewery Lake	Beltrami	MN	B	120 ft	16.0K acres	21
84	West Pike Lake	Cook	MN	A	120 ft	788.2 acres	5
85	Elkhart Lake	Sheboygan	WI	A	119 ft	292 acres	7
86	Long Lake	Aitkin	MN	B	116 ft	434.72 acres	16
87	Ima Lake	Lake	MN	B	116 ft	741.91 acres	0
88	Ottertrack Lake	Unknown	MN	A	116 ft	1.1K acres	9
89	Long Lake	Cass	MN	A	115 ft	1.0K acres	14
90	Wabana Lake	Itasca	MN	A	115 ft	2.2K acres	14
91	Long Lake	Cass	MN	A	115 ft	1.0K acres	14
92	Minnetonka Lake	Hennepin	MN	B	113 ft	14.2K acres	18
93	Pine Lake	Cook	MN	A	113 ft	2.1K acres	10
94	Pokegama Lake	Itasca	MN	A	112 ft	6.7K acres	19
95	Pokegama Lake	Itasca	MN	A	112 ft	6.7K acres	19
96	Greenwood Lake	Cook	MN	A	112 ft	2.0K acres	10
97	Rabideau Lake	Beltrami	MN	C	112 ft	680.35 acres	14
98	Washburn Lake	Cass	MN	A	111 ft	1.6K acres	21
99	Basswood Lake	Lake	MN	C	111 ft	26.0K acres	14
100	Sucker Lake	Lake	MN	B	111 ft	26.0K acres	14

Frequently Asked Questions

Why are deep lakes important for water quality?

Deep lakes maintain a thermocline (temperature barrier) that keeps bottom water cold and oxygen-rich throughout summer. This supports coldwater fish species like lake trout and cisco that cannot survive in shallower, warmer lakes. Deep lakes also resist algae blooms better because their large volume dilutes nutrients.

What is the deepest lake in Minnesota and Wisconsin?

The deepest lakes in both states exceed 200 feet. These deep lakes are typically located in geologically carved basins from glacial activity and offer some of the best water quality and coldwater fishing in the region.