Upper Bottle Lake

Upper Bottle Lake sits at the top of the Minnesota PCA grading rubric with an A, a mark reached by the cleanest lakes in Minnesota. Sub-grades cluster within a single letter of each other, which usually means the lake is in stable trophic balance rather than fighting one specific stressor.

The lake's low TSI puts it in oligotrophic territory — the cleanest of the four trophic classes, but also the most vulnerable to nutrient-driven shifts. Upper Bottle Lake is unusually deep for Minnesota at 55 ft, which buffers the lake against summer warming and helps the deep water stay oxygenated. The lake's 459 acres and 4.0 miles of shoreline put it in the mid-range bucket — large enough for varied use, small enough that watershed inputs reach the whole basin. Upper Bottle Lake ranks 7 of 77 in Hubbard County, putting it in the upper tier of locally monitored lakes.

An invasive species record — faucet snail — has been logged at Upper Bottle Lake; Minnesota PCA maintains the official infested-waters list. The fishery includes walleye alongside the lake's other 14 documented species — a notable draw for Minnesota anglers. A documented public access point at Upper Bottle Lake makes the lake usable for shore fishing, paddle craft, and trailered boats. The lake has a long ice-out record — 29 observations on file, with a median ice-out around Apr 23. The grade is based on limited monitoring — fewer than three independent measurement years contribute, so future updates may shift the letter.