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Portage Lake and Sugar Lake read the same on nutrients and algae. Both are in Minnesota.

Reviewed by LakeQuality Editorial Team · Updated

Both Portage Lake and Sugar Lake sit in Minnesota. A same-state comparison strips out the state-level water-quality regime as a variable: any differences in the readings here are about the lakes themselves, not the agencies sampling them. The readings are close: Portage Lake and Sugar Lake sit within a narrow band of each other on phosphorus, chlorophyll-a and clarity. The per-parameter table below shows where the small differences actually live.

With readings 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.

Portage Lake

Cass County, Minnesota

Moderate clarity, visible to about 7.5 ft.

Sugar Lake

Itasca County, Minnesota

Moderate clarity, visible to about 8.4 ft.

Side-by-Side Metrics

MetricPortage LakeSugar Lake
Water Clarity7.5 ft8.4 ft Better
Phosphorus22 µg/L18 µg/L Better
Chlorophyll-a (Algae)7.1 µg/L4.9 µg/L Better
Maximum Depth55 ft Better22 ft
Surface Area1,539 acres1,509 acres
Public AccessYesYes
Fish Species15 Better13
Trophic Statemesotrophicmesotrophic

A green ✓ marks the better value for that metric (lower phosphorus / chlorophyll = cleaner; higher Secchi / depth / species count = better). Surface area and trophic state carry no tick — a bigger lake is not a better lake.

Verdict

Both lakes earn the same Grade C. The tiebreakers come down to clarity (Portage Lake: 7.5 ft, Sugar Lake: 8.4 ft) and what you want from the lake. Portage Lake supports more documented fish species.

Source: EPA National Aquatic Resource Surveys, 2026.