Markham Lake

Markham Lake grades an F: every scored parameter (clarity) rates poorly, placing it among the most stressed lakes monitored in Minnesota.

At a TSI of 61, Markham Lake reads as eutrophic — nutrient-rich enough that summer algal growth and reduced clarity are expected, not unusual. A maximum depth of 29 ft puts Markham Lake in the middle of Minnesota's depth distribution. Markham Lake covers 229 acres alongside 3.7 miles of shoreline — a mid-sized water that supports a working fishery without being so large that conditions diverge between basins. Markham Lake ranks 186 of 187 in St. Louis County — at the lower end of the locally monitored distribution.

Markham Lake has no invasive species recorded in Minnesota state databases as of 2023, though prevention practices still apply at all access points. The state fisheries records do not list documented species for Markham Lake, which usually reflects a lack of formal fisheries survey work rather than an empty lake. No formal public access is documented at Markham 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.