Dark Lake

Dark Lake earns a D — measurements through 2025 show persistent nutrient pressure that limits clarity through the summer. Clarity, phosphorus, and chlorophyll-a all rate similarly, so there is no obvious single lever to pull on watershed management.

At a TSI of 63, Dark Lake reads as eutrophic — nutrient-rich enough that summer algal growth and reduced clarity are expected, not unusual. At 50 ft of maximum depth, Dark Lake stratifies reliably through the summer — the hypolimnion stays cooler and clearer than the surface layer suggests. Dark Lake covers 120 acres alongside 3.1 miles of shoreline — a mid-sized water that supports a working fishery without being so large that conditions diverge between basins. Dark Lake ranks 9 of 9 in Koochiching County — at the lower end of the locally monitored distribution.

No invasive species are currently listed at Dark Lake — the lake remains off the Minnesota infested-waters roster. The fishery includes walleye alongside the lake's other 10 documented species — a notable draw for Minnesota anglers. A documented public access point at Dark Lake makes the lake usable for shore fishing, paddle craft, and trailered boats. The grade is based on limited monitoring — fewer than three independent measurement years contribute, so future updates may shift the letter.