Big Lasalle Lake

Big Lasalle Lake sits at the top of the Minnesota PCA grading rubric with an A, a mark reached by the cleanest lakes in Minnesota. The three sub-grades — clarity, phosphorus, and chlorophyll-a — track close together, so no single parameter is dragging the average.

A TSI value of 40 puts Big Lasalle Lake in the oligotrophic range, where biological productivity stays low and the water column remains clear. A maximum depth of 48 ft puts Big Lasalle Lake in the middle of Minnesota's depth distribution. At 235 acres, Big Lasalle Lake fits the Minnesota median for monitored lakes, with 3.3 miles of shoreline. Among the 40 graded lakes in Clearwater County, Big Lasalle Lake sits at rank 18, above the county median.

No invasive species are currently listed at Big Lasalle Lake — the lake remains off the Minnesota infested-waters roster. Walleye are documented at Big Lasalle Lake, one of 14 fish species on record for the lake. A documented public access point at Big Lasalle Lake makes the lake usable for shore fishing, paddle craft, and trailered boats. Ice-out has been recorded 9 times at Big Lasalle Lake, with a median around Apr 24. 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.