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LakeQuality

Ml-Peterson Lake vs Ml-Thains Lake

Water quality, depth, fish species, and recreation comparison.

Ml-Peterson Lake has a higher water quality grade (B, Good) than Ml-Thains Lake (B, Good). Both are in Mille Lacs County, Minnesota.

Both Ml-Peterson Lake and Ml-Thains Lake sit in Minnesota. A same-state comparison strips out the state-level water-quality regime as a variable: any grade differences here are about the lakes themselves, not the agencies grading them. These two are within a letter of each other on the rubric — Ml-Peterson Lake (B) versus Ml-Thains Lake (B). The deciding factors for a recreational visitor are likely physical (depth, access, fish species) rather than water-quality differences.

With grades this close, the choice between the two lakes turns on non-water-quality factors: depth, fish species, public access, distance from home. The per-lake pages below cover all of those.

B

Ml-Peterson Lake

Mille Lacs County, Minnesota

Moderate clarity, visible to about 7.4 ft.

B

Ml-Thains Lake

Mille Lacs County, Minnesota

Murky, only visible to about 5.3 ft.

Side-by-Side Metrics

Source: EPA National Aquatic Resource Surveys, 2026.

Source: EPA National Aquatic Resource Surveys, 2026.

Source: EPA National Aquatic Resource Surveys, 2026.

Source: EPA National Aquatic Resource Surveys, 2026.

Source: EPA National Aquatic Resource Surveys, 2026.

Source: EPA National Aquatic Resource Surveys, 2026.

Source: EPA National Aquatic Resource Surveys, 2026.

Source: EPA National Aquatic Resource Surveys, 2026.

Source: EPA National Aquatic Resource Surveys, 2026.

MetricMl-Peterson LakeMl-Thains Lake
Overall GradeB (Good)B (Good)
Water Clarity7.4 ft5.3 ft
Phosphorus26.5 µg/L26 µg/L
Chlorophyll-a (Algae)3.9 µg/L3.5 µg/L
Maximum Depth42 ft42 ft
Surface Area128.3K acres128.3K acres
Public AccessYesYes
Fish Species11
Trophic Statemesotrophicmesotrophic

Bold value = better for that metric (lower phosphorus / chlorophyll = cleaner; higher Secchi / depth / species count = better).

Verdict

Ml-Peterson Lake wins on overall water quality with a Grade B versus Ml-Thains Lake's Grade B. Water clarity: 7.4 ft vs 5.3 ft. For fishing diversity, Ml-Peterson Lake also leads with 1 species.