Magnetic Lake

Cook County, Minnesota - DNR stocking history, depth and survey data

Minnesota · Minnesota Department of Natural Resources (DNR) · DOW 16046300

Magnetic Lake has no DNR stocking rows in LakeFinder; this page carries its DNR depth, access and survey data.

• Magnetic Lake shows no stocking records in Minnesota DNR LakeFinder as of September 2, 2026.
• Maximum depth 90 ft; surface area 447 acres, 95 littoral acres, 10.1 miles of shoreline, per the DNR lake survey.
• Average water clarity (Secchi depth) 14.2 ft.
• Fish species DNR lists here: burbot, lake trout, rock bass, smallmouth bass, tullibee (cisco), walleye, white sucker, yellow perch.
• 1 public access on the DNR list.
• Most recent DNR fish survey: August 13, 2025 (targeted survey).
• Cook County, nearest town Maple Hill; DNR lake number (DOW) 16046300.

Depth map

Bathymetric contours from the Minnesota DNR lake survey; depths in feet. Simplified for the web; not for navigation.

Public accesses

DNR fish survey, 2025

Temperature and dissolved oxygen (DO) measurements were collected from the deepest basin in Magnetic Lake on August 13th, 2025, to evaluate the quantity and quality of cold, oxygenated water (i.e., oxythermal habitat) available to Lake Trout, the most sensitive coldwater species present in this lake (Cisco, also known as 'Tullibee', are also present). During the summer, Lake Trout require a layer of oxythermal habitat that contains water temperatures below 8.8 degrees C (47.8 degrees F) and dissolved oxygen concentrations above 3.0 mg/L. Based on the profile from the deepest basin (maximum sampled depth 80.4 feet), the water temperature decreased below 8.8 degrees C (47.8 degrees F) at 35.3 feet and the dissolved oxygen concentration stayed greater than 3.0 mg/L at 80.4 feet at the time of sampling. The thickness of this layer of water in the water column was 45.1 feet, indicating that oxythermal habitat was present for Lake Trout. Further, the temperature at which dissolved oxygen decreased to 3.0 mg/L (i.e., TDO3, a single variable to characterize oxythermal habitat) was never reached because dissolved oxygen remained above 3.0 mg/L throughout the sampled depths. In this case, the minimum temperature, 5.9 degrees C (42.6 degrees F), was substituted as TDO3. TDO3 values cooler than 8.8 degrees C (47.8 degrees F) indicate that oxythermal conditions were suitable for Lake Trout at the time of the survey. Data collected by the Minnesota Department of Natural Resources during the late summer period of maximum oxythermal stress (July 26th to Aug 24th) in 3 years, between 1976-2024, also indicate suitable oxythermal habitat in all years surveyed, with the least favorable conditions recorded in 2024 when the suitable oxythermal habitat layer was 38.8 feet thick. When inadequate oxythermal habitat is available, Lake Trout are squeezed into unfavorable, warmer water conditions and experience higher levels of stress.

Minnesota DNR survey narrative, August 13, 2025.

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