Oligotrophic Lakes: Crystal Clear, Low Nutrient Lakes

An oligotrophic lake is what most people picture when they think of pristine northern lake country: clarity to depth, no algal scum, cold water that holds dissolved oxygen all the way to the bottom even in August. Across the United States (49 states), Canada (Ontario, Québec, Nova Scotia, British Columbia and Newfoundland and Labrador), and 38 other country hubs. LakeQuality covers, 100 lakes register as oligotrophic — 62% of them break 50 feet of depth, which is the structural condition that underwrites the trophic class. Without depth and a low-nutrient watershed, oligotrophy is hard to sustain.

Oligotrophic lakes almost always carry the lowest phosphorus and chlorophyll-a readings on record, since the same low-nutrient conditions produce both the trophic class and the clear water.

Lake	County	State	Clarity	Depth
Rainy Lake	Cass	MN	13.9 ft	29 ft
East Fox Lake	Crow Wing	MN	16.4 ft	65 ft
Deep Portage Lake	Cass	MN	15.4 ft	105 ft
Clearwater Lake	Cook	MN	29 ft	65 ft
Lower Hay Lake	Crow Wing	MN	18.5 ft	100 ft
Latoka Lake	Douglas	MN	19 ft	108 ft
Bad Medicine Lake	Becker	MN	25 ft	84 ft
Big Sugar Bush Lake	Becker	MN	16.5 ft	42 ft
Pelican Lake	Crow Wing	MN	14.3 ft	104 ft
Fullers Lake	Beltrami	MN	15 ft	-
Birch Lake	Cook	MN	18 ft	69 ft
Round Lake	Aitkin	MN	14.5 ft	125 ft
Round Lake	Cook	MN	16.5 ft	45 ft
Round Lake	Beltrami	MN	18 ft	38 ft
Ada Lake	Cass	MN	14 ft	60 ft
Pike Lake	Cook	MN	17.4 ft	45 ft
Long Lake	Clearwater	MN	20.5 ft	80 ft
Long Lake	Cass	MN	21.5 ft	115 ft
Long Lake	Beltrami	MN	20 ft	87 ft
Long Lake	Becker	MN	19.5 ft	61 ft
Long Lake	Beltrami	MN	14 ft	-
Long Lake	Itasca	MN	16.7 ft	72 ft
Long Lake	Itasca	MN	16.9 ft	85 ft
Dead Lake	Hubbard	MN	16 ft	34 ft
Maple Lake	Cass	MN	13.3 ft	45 ft
Maple Lake	Itasca	MN	15.3 ft	39 ft
West Twin Lake	Crow Wing	MN	13.3 ft	42 ft
Shallow Lake	Itasca	MN	16.4 ft	85 ft
Trout Lake	Itasca	MN	18 ft	157 ft
Trout Lake	Cook	MN	18.4 ft	77 ft
Deer Lake	Itasca	MN	13.1 ft	121 ft
Cowdry Lake	Douglas	MN	17.1 ft	52 ft
Ossawinnamakee Lake	Crow Wing	MN	20 ft	63 ft
Clear Lake	Crow Wing	MN	18 ft	63 ft
Clear Lake	Itasca	MN	14.9 ft	30 ft
Spectacle Lake	Isanti	MN	13.8 ft	51.5 ft
Bear Lake	Lake	MN	17.4 ft	31 ft
Blue Lake	Hubbard	MN	17.3 ft	84 ft
Eagle Lake	Otter Tail	MN	22.6 ft	46 ft
West Fox Lake	Crow Wing	MN	15 ft	55 ft
Star Lake	Crow Wing	MN	19 ft	83 ft
Fish Lake	Otter Tail	MN	18 ft	69 ft
Benedict Lake	Hubbard	MN	11.5 ft	91 ft
Square Lake	Washington	MN	17 ft	68 ft
Shell Lake	Beltrami	MN	13 ft	-
Woman Lake	Cass	MN	15 ft	-
Green Lake	Beltrami	MN	18.5 ft	-
Girl Lake	Cass	MN	17.6 ft	81 ft
Mow Lake	Hubbard	MN	14.5 ft	34 ft
Charlotte Lake	Wright	MN	17.1 ft	46 ft
Big Mcdonald Lake	Otter Tail	MN	17.4 ft	46 ft
Bass Lake	Otter Tail	MN	17.4 ft	-
Bass Lake	Crow Wing	MN	16.1 ft	47 ft
Bass Lake	Itasca	MN	18.2 ft	65 ft
Island Lake	St. Louis	MN	14.5 ft	65 ft
Island Lake	Crow Wing	MN	15.1 ft	76 ft
Island Lake	Cass	MN	17.5 ft	40 ft
Island Lake	Beltrami	MN	16 ft	-
Island Lake	Hubbard	MN	16.4 ft	32 ft
Moose Lake	Beltrami	MN	15.1 ft	71 ft
Crooked Lake	Hubbard	MN	19 ft	-
Crooked Lake	Crow Wing	MN	15 ft	54 ft
Cedar Lake	Morrison	MN	16.2 ft	88 ft
Big Pine Lake	Aitkin	MN	17 ft	78 ft
Lizzie Lake	Otter Tail	MN	16.4 ft	66 ft
Turtle Lake	Becker	MN	23 ft	73 ft
Turtle Lake	Itasca	MN	17.1 ft	54 ft
Lower Bottle Lake	Hubbard	MN	15 ft	110 ft
Pokegama Lake	Itasca	MN	16.1 ft	112 ft
Sandy Lake	Beltrami	MN	16 ft	-
Pickerel Lake	Becker	MN	18 ft	74 ft
Strawberry Lake	Becker	MN	17.5 ft	40 ft
Gull Lake	Cook	MN	15.5 ft	-
Henderson Lake	Kandiyohi	MN	13.5 ft	57 ft
Upper Birch Lake	Isanti	MN	10.8 ft	-
Upper Bottle Lake	Hubbard	MN	16 ft	55 ft
Courthouse Lake	Carver	MN	18.9 ft	57 ft
Silver Lake	St. Louis	MN	19.3 ft	29 ft
Heart Lake	Beltrami	MN	14.5 ft	-
West Battle Lake	Otter Tail	MN	18 ft	108 ft
Wabana Lake	Itasca	MN	18 ft	115 ft
Roy Lake	Crow Wing	MN	11.7 ft	26 ft
Little Mantrap Lake	Hubbard	MN	17 ft	54 ft
Clitherall Lake	Otter Tail	MN	14.1 ft	69 ft
Kimball Lake	Crow Wing	MN	18.4 ft	77 ft
Baby Lake	Cass	MN	12.5 ft	69 ft
Crystal Lake	Cass	MN	16 ft	40 ft
West Sylvia Lake	Wright	MN	22 ft	97 ft
Serpent Lake	Crow Wing	MN	25 ft	65 ft
North Twin Lake	Beltrami	MN	17.4 ft	59 ft
Stuart Lake	Otter Tail	MN	17.5 ft	49 ft
North Star Lake	Itasca	MN	19 ft	90 ft
Pleasant Lake	Cass	MN	15.5 ft	72 ft
Little Bass Lake	Beltrami	MN	16 ft	22 ft
Pulaski Lake	Wright	MN	18 ft	-
Little Mcdonald Lake	Otter Tail	MN	26.5 ft	109 ft
Bay Lake	Crow Wing	MN	18.5 ft	74 ft
Webb Lake	Cass	MN	18 ft	84 ft
Little Hubert Lake	Crow Wing	MN	18 ft	41 ft
Big Trout Lake	Crow Wing	MN	16.9 ft	128 ft

Frequently Asked Questions

What is an oligotrophic lake?

Low nutrients, clear water, excellent for swimming. There are 100 oligotrophic lakes across the United States (49 states), Canada (Ontario, Québec, Nova Scotia, British Columbia and Newfoundland and Labrador), and 38 other country hubs. LakeQuality covers, representing 2% of all measured lakes.