Crosby Lake

Crosby Lake pulls a D on the LakeGrade rubric — phosphorus loading and limited clarity hold it below the Minnesota average. Clarity, phosphorus, and chlorophyll-a all rate similarly, so there is no obvious single lever to pull on watershed management.

At a TSI of 61, Crosby Lake reads as eutrophic — nutrient-rich enough that summer algal growth and reduced clarity are expected, not unusual. The lake bottoms out at 19 ft — a moderate depth that supports a warm-water fishery without the year-round cold refuge a deeper basin provides. Crosby Lake is small — 69 acres alongside 1.7 miles of shoreline — which makes it sensitive to even modest changes in watershed runoff or recreational pressure. Crosby Lake ranks 38 of 49 in Ramsey County — at the lower end of the locally monitored distribution.

Crosby Lake has no invasive species recorded in Minnesota state databases as of 2024, though prevention practices still apply at all access points. The fishery is bass-led, with 11 documented species across the lake's records. No formal public access is documented at Crosby Lake — most use is by shoreline residents and their guests. The grade is based on limited monitoring — fewer than three independent measurement years contribute, so future updates may shift the letter.