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LakeQuality
A

Craig Lake

Cass County, MinnesotaLimited DataMesotrophic

Craig Lake sits at the top of the Minnesota PCA grading rubric with an A, a mark reached by the cleanest lakes in Minnesota. Clarity, phosphorus, and chlorophyll-a all rate similarly, so there is no obvious single lever to pull on watershed management.

A TSI near 43 places Craig Lake in the mesotrophic band — moderate productivity, with seasonal swings between clearer spring water and richer late-summer conditions. 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. Craig Lake ranks 46 of 133 in Cass County — solidly in the upper half of the local distribution.

No invasive species are currently listed at Craig Lake — the lake remains off the Minnesota infested-waters roster. The state fisheries records do not list documented species for Craig Lake, which usually reflects a lack of formal fisheries survey work rather than an empty lake. The lake lacks a documented public access point, so visitor use is limited. 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.

Source: EPA Water Quality Portal sampling records, Minnesota DNR LakeFinder, last sampled 2019-10-08. Grade methodology: LakeGrade methodology.

Swimming Safety

Excellent for swimming, crystal clear water with minimal algae

Water Quality Grade: A, Excellent

No clarity data. Chlorophyll-a: 3.6 µg/L. Trophic State Index: 43.

MetricValueGrade
Water Clarity (Secchi Depth)No data
PhosphorusNo data
Chlorophyll-a (Algae)3.6 µg/LA
Trophic State Index (TSI)43Mesotrophic

Moderate nutrients, good water quality

Water Quality Trend: Declining

Based on 6 years of monitoring data (2020-2025).

MetricTrendChange/YearYears
Water Clarity Stable-0.037 m/yr5
Phosphorus Declining+1.2 µg/L/yr5
Chlorophyll-a Stable+0.06 µg/L/yr3

Location

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County Ranking

Ranked #46 of 133 lakes in Cass County

Nearby Lakes in Cass County

Data Sources

Water quality data from the EPA Water Quality Portal

Grading methodology based on Metropolitan Council standards

Most recent sample: 2019-10-08

Monitoring stations: 2