Shallow Lakes in Minnesota & Wisconsin

Q: Are shallow lakes safe for swimming?

Many shallow lakes are safe for swimming, especially those with Grade A or B water quality. However, shallow lakes are more prone to algae blooms in late summer due to warmer water temperatures and wind-mixed nutrients. Always check for blue-green algae advisories before swimming.

Q: Why do shallow lakes have more algae?

Shallow lakes warm up faster and wind mixes nutrients from the bottom into the water column, fueling algae growth. Without a thermocline to trap nutrients in deep water, the entire lake becomes a growth zone for algae. This is why shallow lakes are more likely to receive lower water quality grades.

Lakes under 20 feet deep in Minnesota and Wisconsin ranked by water quality. Shallow lakes warm quickly in summer and are great for wading and family swimming, but are more susceptible to algae blooms and winter fish kills.

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

100

Total Lakes

Minnesota

Wisconsin

Rank	Lake	County	State	Grade	Depth	Area	Fish
1	Cramer Lake	Lake	MN	A	4 ft	68.31 acres	5
2	Cabin Lake	Lake	MN	A	3 ft	66.24 acres	3
3	Long Lake	Waushara	WI	A	14 ft	40 acres	3
4	Spider Lake	Bayfield	WI	A	15 ft	66 acres	4
5	Bass Lake	Oconto	WI	A	11 ft	13 acres	3
6	Long Lake Plainfield	Waushara	WI	A	14 ft	40 acres	3
7	Bear Lake	Douglas	WI	A	10 ft	49 acres	5
8	Deep Hole Lake	Langlade	WI	A	10 ft	8 acres	1
9	Clear Lake	Oneida	WI	A	15 ft	41 acres	2
10	Thunder Lake	Oneida	WI	A	9 ft	1.8K acres	4
11	Stewart Lake	Dane	WI	A	12 ft	6 acres	3
12	South Twin Lake	Portage	WI	A	9 ft	54 acres	1
13	Big Bass Lake	Marathon	WI	A	13 ft	177 acres	3
14	Eagle Lake	Burnett	WI	A	15 ft	71 acres	3
15	Vincent Lake	Polk	WI	A	15 ft	58 acres	3
16	Lulu Lake	Shawano	WI	A	13 ft	37 acres	3
17	Aldridge Lake	Vilas	WI	A	12 ft	142 acres	4
18	Lower Phantom Lake	Waukesha	WI	A	12 ft	373 acres	3
19	Como Lake	Chippewa	WI	A	11 ft	98 acres	3
20	Irving Lake	Vilas	WI	A	8 ft	419 acres	4
21	Walsh Lake	Forest	WI	A	15 ft	45 acres	1
22	Little Ripley Lake	Washburn	WI	A	14 ft	39 acres	2
23	Halfmoon Lake	Lincoln	WI	A	14 ft	102 acres	3
24	Morgan Lake	Florence	WI	A	10 ft	44 acres	1
25	Smith Lake	Marinette	WI	A	11 ft	20 acres	0
26	Vern Wolf Lake	Kenosha	WI	A	12 ft	150 acres	4
27	Taylor Lake-Deep Hole	Bayfield	WI	A	15 ft	85 acres	5
28	Catherine Lake	Iron	WI	A	14 ft	136 acres	6
29	Range Line Lake	Vilas	WI	A	13 ft	61 acres	2
30	Mallard Lake	Milwaukee	WI	A	10 ft	16 acres	1
31	Crystal Bog Lake	Vilas	WI	A	8 ft	1 acres	0
32	Park Creek Pond	Douglas	WI	A	7 ft	9 acres	2
33	Sanborn Lake	Vilas	WI	A	13 ft	243 acres	3
34	Tambling Lake	Vilas	WI	A	11 ft	172 acres	4
35	Signalness Lake	Pope	MN	A	14 ft	42.25 acres	9
36	Little Whitefish Lake	Itasca	MN	A	15 ft	160.4 acres	0
37	Hennepin Lake	Hubbard	MN	A	14 ft	417.61 acres	0
38	Outlet of Onamia Lake on the Rum River	Mille Lacs	MN	A	10 ft	1.0K acres	0
39	Outlet of Ogechie Lake on the Rum River	Mille Lacs	MN	A	6 ft	409.14 acres	0
40	Stella Lake	Vilas	WI	A	9 ft	95 acres	3
41	Pine Lake	Forest	WI	A	15 ft	1.7K acres	5
42	Cochran Lake	Vilas	WI	A	12 ft	133 acres	4
43	White Lake	Waupaca	WI	A	10 ft	1.1K acres	5
44	Wilson Lake	Waushara	WI	A	12 ft	75 acres	4
45	Lawrence Lake	Marquette	WI	A	14 ft	217 acres	4
46	Eagle Spring Lake	Waukesha	WI	A	8 ft	279 acres	3
47	Lake Content	Vilas	WI	A	14 ft	239 acres	5
48	Little Portage Lake	Vilas	WI	A	11 ft	160 acres	4
49	East Twin Lake	Marquette	WI	A	8 ft	13 acres	0
50	Bishop Lake	Forest	WI	A	12 ft	288 acres	3
51	Horseshoe Lake	Cass	MN	B	12 ft	127.36 acres	0
52	Shallow Lake	Hubbard	MN	B	10 ft	284.3 acres	13
53	Mill Lake	Becker	MN	B	10 ft	154.5 acres	14
54	Fourteen Lake	St. Louis	MN	B	14.5 ft	386.11 acres	7
55	Pine Lake	Clearwater	MN	B	15 ft	1.2K acres	12
56	Pine Lake	St. Louis	MN	B	14 ft	450.07 acres	8
57	Three Island Lake	Cass	MN	B	13 ft	287.89 acres	8
58	Tait Lake	Cook	MN	B	15 ft	355.09 acres	6
59	Battle Lake	Itasca	MN	B	15 ft	243.32 acres	11
60	Ryan Lake	St. Louis	MN	B	13 ft	33.87 acres	4
61	Laddie Lake	Anoka	MN	B	4 ft	66.13 acres	0
62	Clara Lake	Cook	MN	B	15 ft	387.64 acres	6
63	School Section Lake	Stearns	MN	B	14 ft	210.54 acres	8
64	Dick Lake	Cook	MN	B	12 ft	127.24 acres	5
65	Cable Lake	Polk	MN	B	14 ft	193.51 acres	0
66	North Branch Kawishi Lake	Lake	MN	B	13 ft	181.77 acres	7
67	Town Line Lake	Cass	MN	B	11 ft	697.67 acres	8
68	3-Island Lake	Cass	MN	B	13 ft	287.89 acres	8
69	Sargent Lake	Mahnomen	MN	B	15 ft	137.54 acres	12
70	Crow River Mill Pond	Kandiyohi	MN	B	14 ft	2.3K acres	13
71	Campers Lake	Lake	MN	B	2.5 ft	48.34 acres	5
72	Big Rice Lake	St. Louis	MN	B	5 ft	1.9K acres	0
73	Rice Lake	Polk	WI	B	10 ft	128 acres	3
74	Rice Lake	Forest	WI	B	6 ft	201 acres	3
75	Round Lake	Oneida	WI	B	15 ft	151 acres	6
76	Wyman Lake	Jackson	WI	B	8 ft	7 acres	2
77	White Lake	Shawano	WI	B	11 ft	163 acres	2
78	Pickerel Lake	Lincoln	WI	B	14 ft	49 acres	3
79	Second Lake	Oneida	WI	B	11 ft	103 acres	6
80	Horsehead Lake	Oneida	WI	B	11 ft	377 acres	3
81	Horse Lake	Polk	WI	B	11 ft	221 acres	3
82	North White Ash Lake	Polk	WI	B	9 ft	116 acres	3
83	Mud Lake	Polk	WI	B	15 ft	14 acres	1
84	Augustine Lake	Ashland	WI	B	10 ft	171 acres	4
85	North Lake	Walworth	WI	B	11 ft	255 acres	3
86	Gaslyn Lake	Burnett	WI	B	12 ft	161 acres	3
87	Swamp Lake	Oneida	WI	B	8 ft	293 acres	4
88	Boot Lake	Vilas	WI	B	15 ft	286 acres	5
89	Big Twin Lake	Waushara	WI	B	13 ft	93 acres	3
90	Rolling Stone Lake	Langlade	WI	B	12 ft	682 acres	6
91	Third Lake	Oneida	WI	B	14 ft	97 acres	6
92	Rhinelander Flowage Lake	Oneida	WI	B	10 ft	1.4K acres	6
93	Arkdale Lake	Adams	WI	B	10.5 ft	46 acres	3
94	Deep Hole Lake	Langlade	WI	B	10 ft	18 acres	1
95	Pacwawong Spring Pond	Sawyer	WI	B	14 ft	13 acres	5
96	Unnamed Lake	Langlade	WI	B	8 ft	8 acres	0
97	Unnamed Lake	Douglas	WI	B	6 ft	20 acres	0
98	Hallie Lake	Chippewa	WI	B	13 ft	79 acres	4
99	Christie Lake	Oconto	WI	B	10 ft	398 acres	0
100	Upper Red Lake	Shawano	WI	B	15 ft	195 acres	6

Frequently Asked Questions

Are shallow lakes safe for swimming?

Many shallow lakes are safe for swimming, especially those with Grade A or B water quality. However, shallow lakes are more prone to algae blooms in late summer due to warmer water temperatures and wind-mixed nutrients. Always check for blue-green algae advisories before swimming.

Why do shallow lakes have more algae?

Shallow lakes warm up faster and wind mixes nutrients from the bottom into the water column, fueling algae growth. Without a thermocline to trap nutrients in deep water, the entire lake becomes a growth zone for algae. This is why shallow lakes are more likely to receive lower water quality grades.