Boulder Lake vs Lost Lake
Water quality, depth, fish species, and recreation comparison.
Boulder Lake has a higher water quality grade (B, Good) than Lost Lake (C, Fair). Both are in Vilas County, Wisconsin.
Both Boulder Lake and Lost Lake sit in Wisconsin. A same-state comparison strips out the state-level water-quality regime as a variable: any grade differences here are about the lakes themselves, not the agencies grading them. The grades are close: Boulder Lake (B) and Lost Lake (C) are within one letter of each other on the LakeGrade rubric. The per-parameter sub-grades below will show where the small differences actually live.
With grades this close, the choice between the two lakes turns on non-water-quality factors: depth, fish species, public access, distance from home. The per-lake pages below cover all of those.
Boulder Lake
Murky, only visible to about 5.6 ft.
Lost Lake
Murky, only visible to about 4.5 ft.
Side-by-Side Metrics
| Metric | Boulder Lake | Lost Lake |
|---|---|---|
| Overall Grade | B (Good) | C (Fair) |
| Water Clarity | 5.6 ft | 4.5 ft |
| Phosphorus | 21.6 µg/L | 34.5 µg/L |
| Chlorophyll-a (Algae) | No data | No data |
| Maximum Depth | 23 ft | 20 ft |
| Surface Area | 516 acres | 539 acres |
| Public Access | Yes | Yes |
| Fish Species | 6 | 5 |
| Trophic State | eutrophic | eutrophic |
Bold value = better for that metric (lower phosphorus / chlorophyll = cleaner; higher Secchi / depth / species count = better).
Verdict
Boulder Lake wins on overall water quality with a Grade B versus Lost Lake's Grade C. Water clarity: 5.6 ft vs 4.5 ft. For fishing diversity, Boulder Lake also leads with 6 species.
Source: EPA National Aquatic Resource Surveys, 2026.