Mesotrophic

Mesotrophic Lakes in Minnesota & Wisconsin

Moderate nutrients, good water quality. 1,232 lakes (33% of all graded lakes).

Most well-managed working lakes register as mesotrophic — the band that balances productivity with clarity. 1,232 lakes in Minnesota and Wisconsin sit in the mesotrophic band. About 23% are deep (50+ ft); the rest are shallower basins where watershed management keeps nutrients from pushing the system into eutrophy.

Mesotrophic lakes tend to grade B or C on the LakeGrade rubric — the productive-but-clear band lines up with the middle of the letter grades.

Oligotrophic Mesotrophic Eutrophic Hypereutrophic

Lake	County	State	Grade	Clarity	Depth
Pelican Lake	Otter Tail	MN	A	16.1 ft	55 ft
Birch Lake	Wright	MN	A	15 ft	52 ft
Whitefish Lake	Crow Wing	MN	A	15.1 ft	138 ft
Chippewa Lake	Douglas	MN	A	15.1 ft	95 ft
Little Toad Lake	Becker	MN	A	15 ft	65 ft
Island Lake	Crow Wing	MN	A	-	36 ft
Crooked Lake	Stearns	MN	A	15 ft	35 ft
Mukooda Lake	St. Louis	MN	A	16.6 ft	78 ft
Alexander Lake	Morrison	MN	A	16.5 ft	64 ft
George Lake	Kandiyohi	MN	A	15 ft	34 ft
Brickyard Lake	Carver	MN	A	15.1 ft	43 ft
Little Bass Lake	Clearwater	MN	A	-	35 ft
Little Hubert Lake	Crow Wing	MN	A	18 ft	41 ft
White Bear Lake	Washington	MN	A	15 ft	83 ft
Pine Lake	Cass	MN	A	16 ft	25 ft
Lougee Lake	Crow Wing	MN	A	16 ft	53 ft
Rose Lake	St. Louis	MN	A	-	31 ft
Clamshell Lake	Crow Wing	MN	A	15.1 ft	44 ft
Spring Lake	Hubbard	MN	A	-	36 ft
Lottie Lake	Douglas	MN	A	16.1 ft	31 ft
Edward Lake	Crow Wing	MN	A	15.5 ft	75 ft
South Sugar Lake	Itasca	MN	A	15 ft	36 ft
Grass Lake	Ramsey	MN	A	-	-
Barnesville Lake	Clay	MN	A	-	17 ft
Laxon Lake	Beltrami	MN	A	-	-
Little Sandy Lake	St. Louis	MN	A	-	-
Cramer Lake	Lake	MN	A	-	4 ft
Cabin Lake	Lake	MN	A	-	3 ft
Sioux Lake	Itasca	MN	A	-	34 ft
Craig Lake	Cass	MN	A	-	-
Morph Lake	Itasca	MN	A	-	-
Spring Lake	Waukesha	WI	A	-	22 ft
Spring Lake	Washburn	WI	A	-	24 ft
Black Hawk Lake	Iowa	WI	A	17.2 ft	42 ft
Round Lake	Chippewa	WI	A	18.5 ft	18 ft
Pewaukee Lake	Waukesha	WI	A	18.9 ft	45 ft
Big Lake	Vilas	WI	A	-	30 ft
Lake of the Falls	Iron	WI	A	16.4 ft	23 ft
Turtle Flambeau Flowage Lake	Iron	WI	A	19.7 ft	-
Shadow Lake	Oconto	WI	A	19.7 ft	-
Browns Lake	Racine	WI	A	15.9 ft	44 ft
Lost Lake	Marinette	WI	A	-	18 ft
Van Zile Lake	Forest	WI	A	17.2 ft	17 ft
Long Lake 44-40e	Iron	WI	A	18 ft	34 ft
Rush Lake	Vilas	WI	A	16.4 ft	-
Big Bass Lake	Marathon	WI	A	19.7 ft	13 ft
Blueberry Lake	Vilas	WI	A	-	-
Pike Lake	Polk	WI	A	-	33 ft
Ward Lake	Burnett	WI	A	-	21 ft
Unnamed Lake	Ozaukee	WI	A	-	-
Patrick Lake	Adams	WI	A	16.4 ft	21 ft
Lower Kimball Lake	Washburn	WI	A	19.7 ft	-
Gates Lake	Ashland	WI	A	-	17 ft
Smith Lake	Marinette	WI	A	-	11 ft
Peters Lake	Walworth	WI	A	18.3 ft	-
Taylor Lake-Deep Hole	Bayfield	WI	A	19.7 ft	15 ft
Lake Thirty	Barron	WI	A	15.8 ft	27 ft
Okauchee Lake-Site No. 4-at Okauchee	Waukesha	WI	A	-	90 ft
Okauchee Lake-Site No. 3-at Okauchee	Waukesha	WI	A	-	90 ft
Lk Superior .09 Mi N of Poplar Creek Mouth Lake	Douglas	WI	A	-	-
Cloud Lake	Forest	WI	A	-	25 ft
Tea Lake	Ashland	WI	A	-	48 ft
Trout Bog Lake	Vilas	WI	A	-	24 ft
Crystal Bog Lake	Vilas	WI	A	-	8 ft
Billy Boy Flowage Lake	Sawyer	WI	A	-	46 ft
Little Trout Lake	Vilas	WI	A	-	98 ft
Lake Helen	Portage	WI	A	-	20 ft
Little Mccall Lake	Marinette	WI	A	-	21 ft
Park Creek Pond	Douglas	WI	A	-	7 ft
Round Lake Northeast Site	Chippewa	WI	A	-	18 ft
Sanborn Lake	Vilas	WI	A	-	13 ft
Moss Lake East	Vilas	WI	A	-	29 ft
Amy Bell Lake	Washington	WI	A	-	37 ft
Trego Lake	Washburn	WI	A	-	36 ft
Little Archibald Lake	Oconto	WI	A	-	65 ft
Tambling Lake	Vilas	WI	A	-	11 ft
Moldenhauer Lake	Ozaukee	WI	A	-	32 ft
Greater Bass Lake	Langlade	WI	A	-	25 ft
Csmi 2015 Station Q Lake	Milwaukee	WI	A	-	-
Big Lake	Carlton	MN	A	11.8 ft	25 ft
Crooked Lake	Cass	MN	A	12 ft	74 ft
Ames Lake	Itasca	MN	A	10 ft	51 ft
Lower Birch Lake	Isanti	MN	A	10.8 ft	-
Lost Lake	St. Louis	MN	A	15.1 ft	-
Steamboat Lake	Cass	MN	A	12 ft	93 ft
Third Lake	Carlton	MN	A	10.2 ft	-
Sofie Lake	Carlton	MN	A	15.4 ft	-
Pat Martin Lake	Carlton	MN	A	13.6 ft	-
Lac Lake	Carlton	MN	A	14.6 ft	-
Taylor Lake Deep	Cook	MN	A	10.6 ft	-
Trout Lake Deep	Cook	MN	A	10.7 ft	-
Ml-Thains Lake	Mille Lacs	MN	A	16.1 ft	42 ft
Ml-Seventeen Lake	Aitkin	MN	A	18.8 ft	42 ft
Ml Lake	Mille Lacs	MN	A	20.2 ft	42 ft
Ml Lake	Mille Lacs	MN	A	22.2 ft	42 ft
Ml-Vineland Lake	Mille Lacs	MN	A	25.6 ft	42 ft
Ml-Peterson Lake	Mille Lacs	MN	A	20.2 ft	42 ft
Ml-Malone Lake	Mille Lacs	MN	A	17.5 ft	42 ft
Boxell Lake	Cass	MN	A	14.5 ft	27 ft
East Hunter Lake	Sherburne	MN	A	22.1 ft	-

Showing 100 of 1,232 mesotrophic lakes.

Frequently Asked Questions

What is an mesotrophic lake?

Moderate nutrients, good water quality. There are 1,232 mesotrophic lakes in Minnesota and Wisconsin, representing 33% of all graded lakes.

Can you swim in mesotrophic lakes?

Mesotrophic lakes are generally good for swimming with moderate clarity and low algae risk.

Source: EPA National Aquatic Resource Surveys, 2026.