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LakeQuality

Alexander Lake vs Sullivan Lake

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

Alexander Lake has a higher water quality grade (A, Excellent) than Sullivan Lake (A, Excellent). Both are in Morrison County, Minnesota.

Both Alexander Lake and Sullivan 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 — Alexander Lake (A) versus Sullivan Lake (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.

A

Alexander Lake

Morrison County, Minnesota

Crystal clear, you can see 16.5 ft down.

A

Sullivan Lake

Morrison County, Minnesota

Good clarity, visible to about 10.8 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.

MetricAlexander LakeSullivan Lake
Overall GradeA (Excellent)A (Excellent)
Water Clarity16.5 ft10.8 ft
Phosphorus16.5 µg/L14 µg/L
Chlorophyll-a (Algae)No dataNo data
Maximum Depth64 ft57 ft
Surface Area2.7K acres1.1K acres
Public AccessYesYes
Fish Species11
Trophic Statemesotrophicmesotrophic

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

Verdict

Alexander Lake wins on overall water quality with a Grade A versus Sullivan Lake's Grade A. Water clarity: 16.5 ft vs 10.8 ft. For fishing diversity, Alexander Lake also leads with 1 species.