Boulder Lake vs Little Trout Lake
Water quality, depth, fish species, and recreation comparison.
Boulder Lake and Little Trout Lake read the same on nutrients and algae. Both are in Vilas County, Wisconsin.
Boulder Lake and Little Trout Lake are both in Wisconsin — a same-state head-to-head where the comparison comes down to lake-specific differences in depth, watershed, and monitoring history rather than the broader state-level water-quality regime. The readings are close: Boulder Lake and Little Trout Lake sit within a narrow band of each other on phosphorus, chlorophyll-a and clarity. The per-parameter table below shows where the small differences actually live.
With readings 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.
Little Trout Lake
No clarity data.
Side-by-Side Metrics
| Metric | Boulder Lake | Little Trout Lake |
|---|---|---|
| Water Clarity | 5.6 ft | No data |
| Phosphorus | 21.6 µg/L | 13 µg/L Better |
| Chlorophyll-a (Algae) | No data | No data |
| Maximum Depth | 23 ft | 98 ft Better |
| Surface Area | 516 acres | 1,007 acres |
| Public Access | Yes | Unknown |
| Fish Species | 6 | 6 |
| Trophic State | eutrophic | mesotrophic |
A green ✓ marks the better value for that metric (lower phosphorus / chlorophyll = cleaner; higher Secchi / depth / species count = better). Surface area and trophic state carry no tick — a bigger lake is not a better lake.
Swap a lake
Compare Boulder Lake or Little Trout Lake against a different lake.
Verdict
Both lakes earn the same Grade B. The tiebreakers come down to what you want from the lake. Boulder Lake matches its peer on species count.
Source: EPA National Aquatic Resource Surveys, 2026.