Mantrap Lake

On the LakeGrade rubric, Mantrap Lake pulls an A: clarity at 12.0 ft and 17 µg/L of phosphorus put it in the top bracket for Minnesota. Clarity, phosphorus, and chlorophyll-a all rate similarly, so there is no obvious single lever to pull on watershed management.

The lake sits in the mesotrophic zone — the band where most well-managed Minnesota lakes fall. The lake's maximum depth is not yet documented in state morphometric records — context for its physical structure remains limited. The lake's surface area is not consistently recorded across state datasets — physical context remains partial. Mantrap Lake ranks 33 of 77 in Hubbard County — solidly in the upper half of the local distribution.

Eurasian watermilfoil is established at Mantrap Lake, which can dampen recreational access and pressure the native plant community. The state fisheries records do not list documented species for Mantrap Lake, which usually reflects a lack of formal fisheries survey work rather than an empty lake. A documented public access point at Mantrap Lake makes the lake usable for shore fishing, paddle craft, and trailered boats. The grade is based on limited monitoring — fewer than three independent measurement years contribute, so future updates may shift the letter.