Upper Cullen Lake

Upper Cullen Lake comes in at a B on the grading rubric — a respectable showing for a Minnesota lake of its size and depth. Clarity, phosphorus, and chlorophyll-a all rate similarly, so there is no obvious single lever to pull on watershed management.

Mesotrophic conditions dominate at Upper Cullen Lake: enough nutrients for a healthy fishery, not so much that algal blooms become a chronic problem. A maximum depth of 40 ft puts Upper Cullen Lake in the middle of Minnesota's depth distribution. The lake's 441 acres and 4.9 miles of shoreline put it in the mid-range bucket — large enough for varied use, small enough that watershed inputs reach the whole basin. Within the 120 graded lakes of Crow Wing County, Upper Cullen Lake sits at rank 99, near the bottom of the county list.

No invasive species are currently listed at Upper Cullen Lake — the lake remains off the Minnesota infested-waters roster. The fishery includes walleye alongside the lake's other 14 documented species — a notable draw for Minnesota anglers. No formal public access is documented at Upper Cullen Lake — most use is by shoreline residents and their guests. The lake has a partial ice record — 18 observed ice-outs, centered near Apr 12. 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.