Boulder Lake

Boulder Lake sits at the top of the Wisconsin DNR grading rubric with an A, a mark reached by the cleanest lakes in Wisconsin. Sub-grades cluster within a single letter of each other, which usually means the lake is in stable trophic balance rather than fighting one specific stressor.

Mesotrophic conditions dominate at Boulder Lake: enough nutrients for a healthy fishery, not so much that algal blooms become a chronic problem. A maximum depth of 23 ft puts Boulder Lake in the middle of Wisconsin's depth distribution. At 516 acres, Boulder Lake fits the Wisconsin median for monitored lakes, with partial shoreline records. Within the 202 graded lakes of Vilas County, Boulder Lake sits at rank 156, near the bottom of the county list.

Boulder Lake has at least one documented invasive species (Banded Mystery Snail), so boaters and anglers should observe clean-drain-dry steps when leaving the lake. Walleye are documented at Boulder Lake, one of 6 fish species on record for the lake. A documented public access point at Boulder Lake makes the lake usable for shore fishing, paddle craft, and trailered boats. 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.