Boulder Lake vs Forest Lake
Water quality, depth, fish species, and recreation comparison.
Boulder Lake and Forest Lake read the same on nutrients and algae. Both are in Vilas County, Wisconsin.
Both Boulder Lake and Forest Lake sit in Wisconsin. A same-state comparison strips out the state-level water-quality regime as a variable: any differences in the readings here are about the lakes themselves, not the agencies sampling them. These two sit close on the readings, Boulder Lake versus Forest Lake. The deciding factors for a recreational visitor are likely physical (depth, access, fish species) rather than water-quality differences.
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.
Forest Lake
Crystal clear, you can see 22.2 ft down.
Side-by-Side Metrics
| Metric | Boulder Lake | Forest Lake |
|---|---|---|
| Water Clarity | 5.6 ft | 22.2 ft Better |
| Phosphorus | 21.6 µg/L | 12.8 µg/L Better |
| Chlorophyll-a (Algae) | No data | No data |
| Maximum Depth | 23 ft | 60 ft Better |
| Surface Area | 516 acres | 468 acres |
| Public Access | Yes | Yes |
| Fish Species | 6 Better | 5 |
| Trophic State | eutrophic | oligotrophic |
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 Forest Lake against a different lake.
Verdict
Both lakes earn the same Grade B. The tiebreakers come down to clarity (Boulder Lake: 5.6 ft, Forest Lake: 22.2 ft) and what you want from the lake. Boulder Lake supports more documented fish species.
Source: EPA National Aquatic Resource Surveys, 2026.