Namakan Lake
St. Louis County, MinnesotaLimited DataMesotrophic
The LakeGrade rubric puts Namakan Lake at a C: clarity at 8.2 ft, phosphorus readings still being added, and a TSI of 47 signal an intermediate trophic state.
The lake sits in the mesotrophic zone — the band where most well-managed Minnesota lakes fall. At 150 ft of maximum depth, Namakan Lake stratifies reliably through the summer — the hypolimnion stays cooler and clearer than the surface layer suggests. Namakan Lake covers 24,066 acres alongside 319.9 miles of shoreline, large enough that conditions can vary meaningfully between bays. Namakan Lake ranks 83 of 187 in St. Louis County — solidly in the upper half of the local distribution.
An invasive species record — spiny waterflea — has been logged at Namakan Lake; Minnesota PCA maintains the official infested-waters list. Walleye are documented at Namakan Lake, one of 18 fish species on record for the lake. No formal public access is documented at Namakan Lake — most use is by shoreline residents and their guests. 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 2023-08-22. Grade methodology: LakeGrade methodology.
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Swimming Safety
Generally safe for swimming, moderate water quality
Water Quality Grade: C, Fair
Moderate clarity, visible to about 8.2 ft. Trophic State Index: 47.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 8.2 ft | C |
| Phosphorus | No data | |
| Chlorophyll-a (Algae) | No data | |
| Trophic State Index (TSI) | 47 | Mesotrophic |
Moderate nutrients, good water quality
Lake Details
| Characteristic | Value |
|---|---|
| Maximum Depth | 150 ft |
| Average Depth | 44.5 ft |
| Surface Area | 24.1K acres |
| Shoreline Length | 319.9 mi |
| Littoral Zone | 21% |
| Public Access | No |
Fish Species
Click a species to see all Minnesota and Wisconsin lakes where it is found.
→ Best fishing times for Namakan Lake (14-day solunar calendar)
→ Is it safe to eat fish from Namakan Lake? (mercury & PFAS guide)
→ Namakan Lake fishing regulations (limits, seasons, special rules)
Invasive & Introduced Species
Red chips are ecologically harmful invasive species. Gray chips are stocked or introduced fish that aren't a current ecological concern.
Ice Season
Historical ice data from Minnesota DNR (5 observations).
| Earliest | Latest | |
|---|---|---|
| Ice-Out | 2012-04-01 (2012) | 2014-05-14 (2014) |
| Ice-In | 2024-01-04 (2024) | 2024-01-04 (2024) |
Most recent ice-out: 2019-04-30
Location
County Ranking
Ranked #83 of 187 lakes in St. Louis County
Nearby Lakes in St. Louis County
More Minnesota Lake Rankings
Other Grade C Lakes in Minnesota
Mesotrophic Lakes in Minnesota
Compare Namakan Lake With Nearby Lakes
DNR Fisheries Survey Summary
42 surveys on file from MN DNR Fisheries. Most recent: 2025-09-22 (Standard Survey).
Top Species by Catch Rate
| Species | Avg CPUE | Avg Weight |
|---|---|---|
| Tullibee (Cisco) | 10.60 | 0.78 lb |
| CIS | 10.21 | 0.94 lb |
| Walleye | 7.41 | 0.89 lb |
| Yellow Perch | 5.67 | 0.16 lb |
| TRP | 2.85 | 0.01 lb |
| SAR | 2.27 | 0.28 lb |
CPUE = catch per unit effort, averaged across surveys (excludes juvenile shoreline seining). Higher CPUE = more abundant in standardized sampling.
Length Distributions
Number of fish caught at each inch class in the most recent survey that recorded lengths. Red dashed line marks an approximate trophy threshold for that species.
Tullibee (Cisco)
CIS
Walleye
Yellow Perch
From the 2025-09-22 survey
Namakan Lake is a class 2 lake located on the Minnesota-Ontario border within Voyageurs National Park (VNP). The total surface area is 24,066 acres, of which 49% or 11,755 acres lie within Minnesota. Namakan Lake is typical of lakes within the Canadian Shield with soft, oligotrophic water and intermediate…
DNR Reports & Resources
Minnesota DNR LakeFinder publishes lake survey, fish stocking, water access, and aquatic plant data for Namakan Lake. 1 report on file.
- —Fisheries Lake Survey — NamakanFisheries Lake Survey · MN DNR LakeFinder
EPA Impairment Status
Namakan Lake is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 5).
Causes of impairment
Source: EPA ATTAINS assessment unit MN69-0693-00 · Official waterbody report
Data Sources
Water quality data from the EPA Water Quality Portal
Impairment status from EPA ATTAINS 303(d) database
Grading methodology based on Metropolitan Council standards
Lake details from Minnesota DNR LakeFinder
Ice data from Minnesota DNR Climate
Most recent sample: 2023-08-22
Monitoring stations: 1