Lake of the Woods
Lake of the Woods County, MinnesotaEutrophic
Lake of the Woods earns a C — middle-of-the-pack water quality, with one or two parameters dragging the average down from a stronger grade. Clarity is the limiting factor — phosphorus is reasonable but suspended particles or algal cells keep water transparency below Minnesota norms.
At a TSI of 53, Lake of the Woods reads as eutrophic — nutrient-rich enough that summer algal growth and reduced clarity are expected, not unusual. The lake's maximum depth is not yet documented in state morphometric records — context for its physical structure remains limited. The lake's surface area is not consistently recorded across state datasets — physical context remains partial. Within Lake of the Woods County's 11 graded waters, Lake of the Woods sits at rank 1, near the top of the local distribution.
Lake of the Woods is on the Minnesota infested-waters list for zebra mussels — boaters should follow clean-drain-dry protocols when moving gear to or from the lake. The state fisheries records do not list documented species for Lake of the Woods, which usually reflects a lack of formal fisheries survey work rather than an empty lake. A documented public access point at Lake of the Woods makes the lake usable for shore fishing, paddle craft, and trailered boats. Monitoring depth is thin here: the LakeGrade rubric is applied to a small number of sample years, and the grade will be revised as more data accumulates.
Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2021-09-21. Grade methodology: LakeGrade methodology.
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Swimming Safety
Generally safe for swimming, moderate water quality
Water Quality Grade: C, Fair
Murky, only visible to about 4.8 ft. Phosphorus level: 26 µg/L. Trophic State Index: 53.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 4.8 ft | D |
| Phosphorus | 26 µg/L | B |
| Chlorophyll-a (Algae) | No data | |
| Trophic State Index (TSI) | 53 | Eutrophic |
High nutrients, frequent algae, reduced clarity
Invasive & Introduced Species
Red chips are ecologically harmful invasive species. Gray chips are stocked or introduced fish that aren't a current ecological concern.
Water Quality Trend: → Stable
Based on 3 years of monitoring data (2020-2025).
| Metric | Trend | Change/Year | Years |
|---|---|---|---|
| Water Clarity | ↓ Declining | -0.246 m/yr | 3 |
| Phosphorus | ↑ Improving | -0.75 µg/L/yr | 3 |
Ice Season
Historical ice data from Minnesota DNR (6 observations).
| Earliest | Latest | |
|---|---|---|
| Ice-Out | 1976-04-26 (1976) | 1996-05-19 (1996) |
| Ice-In | 1986-11-11 (1986) | 1988-11-17 (1988) |
Most recent ice-out: 1997-05-06
Location
County Ranking
Ranked #1 of 11 lakes in Lake of the Woods County
Nearby Lakes in Lake of the Woods County
More Minnesota Lake Rankings
State Parks Near Lake of the Woods
Other Grade C Lakes in Minnesota
Eutrophic Lakes in Minnesota
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Lake of the Woods. 1 report on file.
- —Public Water Access Sites — Lake of the Woods (Main)Public Water Access Sites · MN DNR LakeFinder
Data Sources
Water quality data from the EPA Water Quality Portal
Grading methodology based on Metropolitan Council standards
Ice data from Minnesota DNR Climate
Most recent sample: 2021-09-21
Monitoring stations: 1