Forest Lake

On the LakeGrade rubric, Forest Lake pulls an A: clarity at 23.0 ft and phosphorus readings still being added put it in the top bracket for Wisconsin. Clarity, phosphorus, and chlorophyll-a all rate similarly, so there is no obvious single lever to pull on watershed management.

A TSI value of 32 puts Forest Lake in the oligotrophic range, where biological productivity stays low and the water column remains clear. The lake's 60 ft maximum depth is in the upper tier for Wisconsin — deep enough for cold-water fish to find refuge in summer. The lake's 468 acres and partial shoreline records put it in the mid-range bucket — large enough for varied use, small enough that watershed inputs reach the whole basin. Within Vilas County's 191 graded waters, Forest Lake sits at rank 35, near the top of the local distribution.

Eurasian watermilfoil has been documented at Forest Lake, requiring shoreline management to keep dense mats from crowding native vegetation. The fishery includes walleye alongside the lake's other 5 documented species — a notable draw for Wisconsin anglers. Public access is available — the lake is on the Wisconsin DNR public-access list. The grade is based on limited monitoring — fewer than three independent measurement years contribute, so future updates may shift the letter.