Deepest Lakes in Minnesota

The deepest lake in Minnesota is Gilbert Pit Lake at 443 ft in St. Louis County — the single deepest of 50 Minnesota lakes with measured depth, all ranked below by maximum depth.

Lakes with depth data

443

Deepest (ft)

140

Median of top 50

8/50

Reservoirs (vs natural)

Reading Minnesota's depth profile

Gilbert Pit Lake in St. Louis County tops the Minnesota depth ranking at 443 feet. At that depth, Gilbert Pit Lake is in a small national cohort of deep glacial or fault-formed lakes — depth alters everything about the lake's ecology, from thermal stratification through fish-species mix through how well the deep water exchanges with the surface. Lakes this deep typically hold cold-water species (lake trout, cisco, deep-water sculpin) that warmer shallow lakes cannot support.

Minnesota has a wide range of lake depths — the dataset tracks 50 lakes in the depth ranking, with median maximum depth around 140 feet. That spread reflects the state's geological mix: deep glacial basins where ice sheets gouged the bedrock, shallower kettle ponds left by isolated ice blocks, and reservoir lakes that follow the contour of impounded river valleys. The ranking below covers the depth range from the headline maximum to the smaller-but-still-distinctive deep lakes worth visiting.

Maximum-depth data comes from a mix of state Department of Natural Resources bathymetric surveys, U.S. Army Corps of Engineers reservoir records, and USGS hydrographic data. Coverage varies — some states have published bathymetric atlases that cover every lake above a size threshold; others have systematic data only for state-park lakes, fishing waters, or reservoirs. Depth values shown reflect the deepest point ever measured, which is the standard but not the only way to describe a lake's depth (mean depth is a better predictor of thermal behavior).

Top 50 Deepest Lakes in Minnesota (by max depth)

#	Lake	County	Max depth	Mean depth	Surface area	Grade
1	Gilbert Pit Lake	St. Louis	443 ft	—	243.41 ac	B
2	St James Pit Lake	St. Louis	381 ft	114.7 ft	124.18 ac	A
3	Iron Chief Complex Lake	St. Louis	262.1 ft	—	207.44 ac	A
4	Lasalle Lake	Hubbard	213 ft	81 ft	237.9 ac	B
5	Watap Lake	Cook	210 ft	—	1,992.66 ac	C
6	Sagamore Mine Lake	Crow Wing	210 ft	63.4 ft	118.52 ac	A
7	Gabimichigami Lake	Cook	209 ft	—	1,186.15 ac	B
8	Ten Mile Lake	Cass	208 ft	52.4 ft	5,080.41 ac	A
9	Loon Lake	Cook	202 ft	—	1,095.49 ac	A
10	Gunflint Lake	Cook	200 ft	—	4,009.12 ac	A
11	Strup Lake	Lake	195 ft	—	1,688.66 ac	B
12	Sand Point Lake	St. Louis	184 ft	—	8,526.51 ac	C
13	Larson Lake	Itasca	177 ft	—	208.18 ac	A
14	Lac la Croix Lake	St. Louis	168 ft	—	29,596.66 ac	C
15	Crooked Lake	Lake	165 ft	37 ft	10,359.52 ac	C
16	Carlos Lake	Douglas	163 ft	50 ft	2,605.11 ac	A
17	Rainy Lake	Koochiching	161 ft	32 ft	210,200.2 ac	D
18	Rainy Lake	St. Louis	161 ft	32 ft	210,200.2 ac	D
19	Trout Lake	Itasca	157 ft	—	1,743.4 ac	A
20	Caribou Lake	Itasca	152 ft	—	246.5 ac	A
21	Namakan Lake	St. Louis	150 ft	44.5 ft	24,066.28 ac	C
22	Little Saganaga Lake	Cook	150 ft	—	1,627.27 ac	C
23	Snowbank Lake	Lake	150 ft	—	4,654.83 ac	A
24	Steamboat Bay Lake	Cass	150 ft	18.5 ft	103,443.8 ac	B
25	Six Lake	Otter Tail	140 ft	—	196.53 ac	A
26	Elmo Lake	Washington	140 ft	31 ft	256.82 ac	A
27	South Lake	Cook	140 ft	—	1,144.75 ac	A
28	Miner'S Pit West Lake	St. Louis	140 ft	—	141.17 ac	A
29	Whitefish Lake	Crow Wing	138 ft	—	7,714.16 ac	A
30	Rose Lake	Otter Tail	137 ft	—	1,200.47 ac	A
31	Long Lake	Hubbard	135 ft	31 ft	1,926.11 ac	A
32	Big Sand Lake	Hubbard	135 ft	—	1,638.65 ac	A
33	Kabekona Lake	Hubbard	133 ft	53 ft	2,433.39 ac	A
34	Koronis Lake	Stearns	132 ft	29 ft	2,968.28 ac	C
35	Rose Lake	Cook	130 ft	46.8 ft	476.95 ac	B
36	Kekekabic Lake	Lake	130 ft	—	54.91 ac	A
37	Oyster Lake	St. Louis	130 ft	—	762.91 ac	D
38	Mountain Lake	Unknown	130 ft	42 ft	1,344.33 ac	A
39	Rove Lake	Cook	130 ft	42 ft	1,344.33 ac	C
40	Roosevelt Lake	Cass	129 ft	—	1,510.58 ac	A
41	Long Lake	Otter Tail	128 ft	—	1,289.21 ac	B
42	Big Trout Lake	Crow Wing	128 ft	52 ft	1,366.29 ac	A
43	Burntside Lake	St. Louis	126 ft	—	7,313.87 ac	A
44	Round Lake	Aitkin	125 ft	—	736.65 ac	A
45	Jasper Lake	Cook	125 ft	31 ft	245.78 ac	B
46	Mina Lake	Douglas	123 ft	28 ft	411.41 ac	A
47	Big Watab Lake	Stearns	123 ft	43.5 ft	245.56 ac	A
48	Deer Lake	Itasca	121 ft	42.1 ft	4,093.48 ac	A
49	Bluewater Lake	Itasca	120 ft	—	364.22 ac	A
50	Otter Tail Lake	Otter Tail	120 ft	—	14,078.61 ac	A

Frequently Asked Questions

What is the deepest lake in Minnesota?

The deepest lake in Minnesota in the LakeGrade dataset is Gilbert Pit Lake in St. Louis County at 443 feet maximum depth. Water quality grade: B, with 11.5 ft Secchi clarity.

How are lake depths measured?

Lake maximum depth (the deepest point at full-pool water level) comes from state DNR bathymetric surveys, USACE dam-design records for reservoirs, and EPA monitoring records. The figures here represent the deepest point ever measured; everyday water level may be lower because of seasonal drawdowns or drought. For mean depth (average across the entire surface) consult each lake's detail page.

Why are some Minnesota lakes so much deeper than others?

Lake depth depends on how the lake formed. Glacial lakes (common in MN, WI, MI, NY) were carved by ice sheets and can exceed 200 ft. Reservoir lakes (common in IA, MO, OK, KS) are shaped by river valley depth at the dam site — typically 50-150 ft at the dam, much shallower upstream. Oxbow lakes and pothole lakes formed by river meandering or glacial pitting tend to be shallower, usually under 30 ft.

Does deeper mean cleaner?

Not directly, but deeper lakes tend to be cleaner on average. Depth creates thermal stratification in summer, isolating cold deep water from surface algal blooms. Deep lakes also resist nutrient resuspension from wind-driven sediment mixing. That said, many deep lakes still suffer from impairment if the watershed loads heavy phosphorus — see each lake's grade and EPA impairment status below.

What's the average depth of Minnesota lakes in this ranking?

Across the top 50 Minnesota lakes by maximum depth, the average max depth is 164 ft and the median is 140 ft (Elmo Lake). Note this is biased toward deeper lakes; the typical Minnesota lake is shallower.

Where to stay near Minnesota's deepest lakes

Planning a trip? Jump to live cabin, resort, and hotel availability near Minnesota's deepest lakes.

Largest lakes in Minnesota →Cleanest lakes in Minnesota →All Minnesota lakes →