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LakeQuality

Ml Lake vs Outlet of Onamia Lake on the Rum River

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

Outlet of Onamia Lake on the Rum River has a higher water quality grade (A, Excellent) than Ml Lake (B, Good). Both are in Mille Lacs County, Minnesota.

Ml Lake and Outlet of Onamia Lake on the Rum River are both in Minnesota — a same-state head-to-head where the comparison comes down to lake-specific differences in depth, watershed, and monitoring history rather than the broader state-level water-quality regime. These two are within a letter of each other on the rubric — Ml Lake (B) versus Outlet of Onamia Lake on the Rum River (A). 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 Lake

Mille Lacs County, Minnesota

Moderate clarity, visible to about 7.8 ft.

A

Outlet of Onamia Lake on the Rum River

Mille Lacs County, Minnesota

No clarity data.

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 LakeOutlet of Onamia Lake on the Rum River
Overall GradeB (Good)A (Excellent)
Water Clarity7.8 ftNo data
Phosphorus25.5 µg/L25 µg/L
Chlorophyll-a (Algae)4.1 µg/L0.6 µg/L
Maximum Depth42 ft10 ft
Surface Area128.3K acres1.0K acres
Public AccessYesNo
Fish Species10
Trophic Statemesotrophicoligotrophic

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

Verdict

Outlet of Onamia Lake on the Rum River wins on overall water quality with a Grade A versus Ml Lake's Grade B. For more fish-species variety, Ml Lake edges ahead with 1 documented species.