Deepest Lakes in Wisconsin

The deepest lake in Wisconsin is Wazee Lake at 350 ft in Jackson County — the single deepest of 50 Wisconsin lakes with measured depth, all ranked below by maximum depth.

Lakes with depth data

350

Deepest (ft)

Median of top 50

6/50

Reservoirs (vs natural)

Reading Wisconsin's depth profile

Wazee Lake in Jackson County tops the Wisconsin depth ranking at 350 feet. At that depth, Wazee 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.

Wisconsin has a wide range of lake depths — the dataset tracks 50 lakes in the depth ranking, with median maximum depth around 87 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 Wisconsin (by max depth)

#	Lake	County	Max depth	Mean depth	Surface area	Grade
1	Wazee Lake	Jackson	350 ft	—	146 ac	A
2	Green Lake	Green Lake	236 ft	—	7,920 ac	B
3	Geneva Lake	Walworth	135 ft	—	5,401 ac	A
4	Elkhart Lake	Sheboygan	119 ft	—	292 ac	A
5	Beaver Dam Lake	Barron	106 ft	—	1,163 ac	A
6	Big Cedar Lake-North Site-Near West Bend	Washington	105 ft	—	937 ac	A
7	Whitefish Lake	Sawyer	105 ft	—	800 ac	A
8	Presque Isle Lake	Vilas	103 ft	—	1,165 ac	A
9	Whitefish Lake	Douglas	102 ft	—	848 ac	A
10	Lower Pine Lake	Polk	102 ft	—	96 ac	A
11	Long Lake	Chippewa	101 ft	—	936 ac	A
12	Sand Lake	Rusk	100 ft	—	272 ac	A
13	Little Trout Lake Deep	Vilas	98 ft	—	1,007 ac	A
14	Clear Lake	Oneida	95 ft	—	873 ac	A
15	Lake Owen	Bayfield	95 ft	—	1,250 ac	A
16	Chippewa Flowage Lake	Sawyer	92 ft	—	14,593 ac	B
17	Jordan Lake	Adams	92 ft	—	233 ac	A
18	Upper Eau Claire Lake	Bayfield	92 ft	—	1,024 ac	A
19	Silver Lake	Barron	91 ft	—	331 ac	A
20	Okauchee Lake	Waukesha	90 ft	—	1,210 ac	A
21	Lac Courte Oreilles Lake	Sawyer	90 ft	—	5,139 ac	A
22	Nagawicka Lake	Waukesha	90 ft	—	981 ac	B
23	Gilas Lake	Marinette	88 ft	—	135 ac	A
24	Hewitt Lake	Iron	88 ft	—	79 ac	A
25	Bear Lake	Barron	87 ft	—	1,348 ac	B
26	Big Crawling Stone Deep Lake	Vilas	87 ft	—	1,483 ac	A
27	Fence Lake Deep	Vilas	86 ft	—	3,483 ac	A
28	Plummer Lake	Vilas	85 ft	—	219 ac	A
29	Black Oak Lake	Vilas	85 ft	—	564 ac	A
30	Pine Lake	Waukesha	85 ft	—	711 ac	A
31	English Lake	Manitowoc	85 ft	—	48 ac	B
32	Diamond Lake	Bayfield	83 ft	—	322 ac	A
33	Lake Mendota	Dane	83 ft	—	9,781 ac	C
34	Sea Lion Lake	Florence	82 ft	—	114 ac	A
35	Swan Lake	Columbia	82 ft	—	407 ac	D
36	Dead Pike Lake	Vilas	80 ft	—	309 ac	B
37	Lake Metonga	Forest	79 ft	—	2,038 ac	A
38	North Lake	Waukesha	78.4 ft	—	440 ac	B
39	Flambeau Lake Deep	Vilas	78 ft	—	1,166 ac	B
40	Middle Kimball Lake	Washburn	77 ft	—	96 ac	A
41	Long Lake	Waupaca	76 ft	—	112 ac	A
42	Little Sissabagama Lake	Sawyer	75 ft	—	308 ac	A
43	Big Carr Lake	Oneida	75 ft	—	209 ac	B
44	Round Lake	Sawyer	74 ft	—	3,294 ac	A
45	Clear Lake	Rusk	74 ft	—	94 ac	A
46	Chain Lake	Chippewa	74 ft	—	454 ac	C
47	Squash Lake	Oneida	74 ft	—	398 ac	A
48	Lake Lucerne	Forest	73 ft	—	1,039 ac	A
49	Birch Lake	Washburn	73 ft	—	364 ac	C
50	Sand Lake	Burnett	73 ft	—	900 ac	A

Frequently Asked Questions

What is the deepest lake in Wisconsin?

The deepest lake in Wisconsin in the LakeGrade dataset is Wazee Lake in Jackson County at 350 feet maximum depth. Water quality grade: A, with 30 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 Wisconsin 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 Wisconsin lakes in this ranking?

Across the top 50 Wisconsin lakes by maximum depth, the average max depth is 97 ft and the median is 87 ft (Big Crawling Stone Deep Lake). Note this is biased toward deeper lakes; the typical Wisconsin lake is shallower.

Where to stay near Wisconsin's deepest lakes

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

Largest lakes in Wisconsin →Cleanest lakes in Wisconsin →All Wisconsin lakes →