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LakeQuality

Long Lake vs Roosevelt Lake

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

Long Lake has a higher water quality grade (A, Excellent) than Roosevelt Lake (A, Excellent). Both are in Cass County, Minnesota.

Both Long Lake and Roosevelt 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. The grades are close: Long Lake (A) and Roosevelt Lake (A) are within one letter of each other on the LakeGrade rubric. The per-parameter sub-grades below will show where the small differences actually live.

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.

A

Long Lake

Cass County, Minnesota

Crystal clear, you can see 21.5 ft down.

A

Roosevelt Lake

Cass County, Minnesota

Good clarity, visible to about 11 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.

MetricLong LakeRoosevelt Lake
Overall GradeA (Excellent)A (Excellent)
Water Clarity21.5 ft11 ft
Phosphorus9 µg/L12 µg/L
Chlorophyll-a (Algae)No dataNo data
Maximum Depth115 ft129 ft
Surface Area1.0K acres1.5K acres
Public AccessYesYes
Fish Species11
Trophic Stateoligotrophicmesotrophic

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

Verdict

Long Lake wins on overall water quality with a Grade A versus Roosevelt Lake's Grade A. Water clarity: 21.5 ft vs 11 ft. For fishing diversity, Long Lake also leads with 1 species.