Rainbow Lake

Rainbow Lake earns an A — water clarity, phosphorus, and chlorophyll-a all rate among the best monitored waters in Vilas County. Clarity, phosphorus, and chlorophyll-a all rate similarly, so there is no obvious single lever to pull on watershed management.

A TSI value of 37 puts Rainbow Lake in the oligotrophic range, where biological productivity stays low and the water column remains clear. A maximum depth of 36 ft puts Rainbow Lake in the middle of Wisconsin's depth distribution. At 148 acres, Rainbow Lake fits the Wisconsin median for monitored lakes, with partial shoreline records. Rainbow Lake ranks 42 of 202 in Vilas County, putting it in the upper tier of locally monitored lakes.

Rainbow Lake has no invasive species recorded in Wisconsin state databases as of 2025, though prevention practices still apply at all access points. The fishery includes walleye alongside the lake's other 6 documented species — a notable draw for Wisconsin anglers. 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.