Clearest Lakes in Minnesota 2026: Top 25 Ranked by Secchi Clarity, LakeQuality

The single clearest lake in Minnesota is St James Pit Lake in St. Louis County, with a Secchi depth of 47.6 feet — meaning a Secchi disk lowered from the surface disappears at that depth. St James Pit Lake holds an overall water quality grade of A. The 25 clearest lakes in Minnesota are ranked below by 2026 measurements.

How clear are Minnesota's clearest lakes?

Across the 2,350 Minnesota lakes with Secchi clarity readings in our 2026 dataset, the 25 clearest range from 22.5 to 47.6 feet of visibility. St James Pit Lake sits at the top, 16.6 ft clearer than the next lake on the list, well above the 24.8-foot median of this leading group — a spread that shows how quickly clarity falls off once you move past a state's handful of truly pristine waters.

The clearest water is not spread evenly. St. Louis County alone accounts for 5 of the 25 top-ranked lakes, with the rest drawn from 9 other counties. That clustering follows the terrain: deep, glacially carved basins ringed by forest take in little sediment or fertilizer runoff, so phosphorus stays low and the water stays transparent.

Clarity and overall health usually align here: 25 of these 25 lakes also earn an A- or B-range overall grade, and they average 108 feet of maximum depth — deeper water resists the wind-driven mixing that keeps sediment suspended in shallow lakes. Where the two diverge — a clear lake carrying a weaker grade — the cause is typically elevated phosphorus that transparency alone can't reveal, which is why our grade combines phosphorus and chlorophyll-a with Secchi depth rather than relying on clarity by itself.

Rank	Lake	County	Secchi Depth	Grade	Max Depth	Area
1	St James Pit Lake	St. Louis	47.6 ft	A	381 ft	124 acres
2	Caribou Lake	Itasca	31 ft	A	152 ft	247 acres
3	Hunter Lake	Cass	31 ft	A	48 ft	182 acres
4	Clearwater Lake	Cook	29 ft	A	65 ft	462 acres
5	Three Island Lake	Itasca	29 ft	A	66 ft	250 acres
6	Holland Lake	Dakota	27.9 ft	A	55 ft	38 acres
7	Kerbs Lake	Otter Tail	27.7 ft	A	-	-
8	Little Mcdonald Lake	Otter Tail	26.5 ft	A	109 ft	1,316 acres
9	South Lake	Cook	26 ft	A	140 ft	1,145 acres
10	Cruiser Lake	St. Louis	25.4 ft	A	91 ft	118 acres
11	Bad Medicine Lake	Becker	25 ft	A	84 ft	803 acres
12	Serpent Lake	Crow Wing	25 ft	A	65 ft	1,116 acres
13	Big Cormorant Lake	Becker	24.8 ft	A	75 ft	3,657 acres
14	Iron Chief Complex Lake	St. Louis	24.5 ft	A	262.1 ft	207 acres
15	Little Wabana Lake	Itasca	24 ft	A	57 ft	116 acres
16	Sagamore Mine Lake	Crow Wing	23.8 ft	A	210 ft	119 acres
17	Miner'S Pit West Lake	St. Louis	23.1 ft	A	140 ft	141 acres
18	Turtle Lake	Becker	23 ft	A	73 ft	196 acres
19	Big Sand Lake	Hubbard	23 ft	A	135 ft	1,639 acres
20	Lost Lake	St. Louis	23 ft	A	44 ft	124 acres
21	Stony Lake	Cass	23 ft	A	50 ft	563 acres
22	Belle Taine Lake	Hubbard	22.8 ft	A	56 ft	1,497 acres
23	Eagle Lake	Otter Tail	22.6 ft	A	46 ft	907 acres
24	Lone Lake	Aitkin	22.5 ft	A	60 ft	433 acres
25	Peter Lake	Cook	22.5 ft	A	120 ft	282 acres

Where to stay near Minnesota's clearest lakes

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Clearest lakes across all states →Cleanest lakes in Minnesota (combined score) →All Minnesota lakes →

Frequently Asked Questions

What is the clearest lake in Minnesota?

St James Pit Lake is the clearest lake in Minnesota by Secchi depth, with water transparency of 47.6 feet. Secchi depth is measured by lowering a black-and-white disk until it disappears from view — deeper readings mean clearer water. Located in St. Louis County, St James Pit Lake holds an overall water quality grade of A.

How is water clarity measured?

Water clarity is measured by Secchi depth, named after the 19th-century Italian astronomer Pietro Angelo Secchi who developed the method. A standardized black-and-white disk is lowered into the water on a rope; the depth (in feet or meters) at which the disk disappears from view is recorded. Greater Secchi depth means clearer water — usually a sign of low sediment, low phosphorus, and limited algae growth.

What makes a lake clear?

Lake clarity is driven by three factors: low suspended sediment (clay, silt), low nutrient load (especially phosphorus, which fuels algae), and low chlorophyll-a (active algae biomass). Deep glacial lakes with rocky basins and forested watersheds — common in northern Minnesota — tend to be clearest because they have little soil runoff and limited nutrient input. Shallow agricultural-watershed lakes are typically less clear because they receive more sediment and fertilizer runoff.

Is the clearest lake the cleanest?

Not always. Clarity (Secchi depth) is one of three indicators we use; the others are total phosphorus and chlorophyll-a. A lake can be very clear but still have elevated phosphorus that just hasn't bloomed yet, or chlorophyll-a from a recent bloom that's still settling. The most reliable measure of overall lake health is the combined grade, which weights all three signals. See our companion cleanest-lakes ranking for Minnesota for the combined-score list.

How does Minnesota compare to other states?

Minnesota's clearest waters compete with the most pristine lakes in our 36-state dataset, where top-tier lakes typically register Secchi depths of 15–25 feet. Nationally, the gold standard is Crater Lake in Oregon (~100 ft) and Lake Tahoe (~65 ft).

Source: EPA National Aquatic Resource Surveys + state DNR Secchi sampling, 2026.