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LakeQuality

Lake St. Croix vs Lake St. Croix

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

Lake St. Croix and Lake St. Croix both received the same overall water quality grade of B (Good).

Lake St. Croix is in Wisconsin; Lake St. Croix is in Minnesota. Cross-state comparisons carry an extra wrinkle — Minnesota PCA and Wisconsin DNR use slightly different sampling cadences and station coverage, though both feed the same EPA Water Quality Portal. These two are within a letter of each other on the rubric — Lake St. Croix (B) versus Lake St. Croix (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

Lake St. Croix

St. Croix County, Wisconsin

Murky, only visible to about 5.6 ft.

B

Lake St. Croix

Washington County, Minnesota

Murky, only visible to about 5.2 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.

MetricLake St. CroixLake St. Croix
Overall GradeB (Good)B (Good)
Water Clarity5.6 ft5.2 ft
Phosphorus16.5 µg/L18 µg/L
Chlorophyll-a (Algae)No dataNo data
Maximum Depth60 ft78 ft
Surface Area7.7K acres8.4K acres
Public AccessUnknownNo
Fish Species01
Trophic Statemesotrophicmesotrophic

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

Verdict

Both lakes earn the same Grade B. The tiebreakers come down to clarity (Lake St. Croix: 5.6 ft, Lake St. Croix: 5.2 ft) and what you want from the lake. Lake St. Croix has fewer fish species than Lake St. Croix.