Gilbert Pit Lake

Gilbert Pit Lake carries a solid B grade — strong on most parameters, with measurements that hold up well across the summer season.

Mesotrophic conditions dominate at Gilbert Pit Lake: enough nutrients for a healthy fishery, not so much that algal blooms become a chronic problem. The lake's 443 ft maximum depth is in the upper tier for Minnesota — deep enough for cold-water fish to find refuge in summer. Gilbert Pit Lake covers 243 acres alongside 5.8 miles of shoreline — a mid-sized water that supports a working fishery without being so large that conditions diverge between basins. Among the 187 graded lakes in St. Louis County, Gilbert Pit Lake sits at rank 73, above the county median.

Zebra mussels have been documented at Gilbert Pit Lake, which alters the filter-feeding balance and can paradoxically increase water clarity while disrupting the food web. The fishery includes walleye among the lake's 10 documented species — a notable draw for Minnesota anglers. Public access is available — the lake is on the Minnesota PCA public-access list. The grade is based on limited monitoring — fewer than three independent measurement years contribute, so future updates may shift the letter.