Andrew Lake vs Mary Lake
Water quality, depth, fish species, and recreation comparison.
Andrew Lake and Mary Lake read the same on nutrients and algae. Both are in Douglas County, Minnesota.
Both Andrew Lake and Mary 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. These two sit close on the readings, Andrew Lake versus Mary Lake. The deciding factors for a recreational visitor are likely physical (depth, access, fish species) rather than water-quality differences.
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.
Andrew Lake
Good clarity, visible to about 13.9 ft.
Mary Lake
Good clarity, visible to about 10.5 ft.
Side-by-Side Metrics
| Metric | Andrew Lake | Mary Lake |
|---|---|---|
| Water Clarity | 13.9 ft Better | 10.5 ft |
| Phosphorus | 17 µg/L Better | 20 µg/L |
| Chlorophyll-a (Algae) | 4 µg/L Better | 5.5 µg/L |
| Maximum Depth | 83 ft Better | 40 ft |
| Surface Area | 923 acres | 2,450 acres |
| Public Access | Yes | Yes |
| Fish Species | 18 Better | 17 |
| Trophic State | mesotrophic | mesotrophic |
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.
Swap a lake
Compare Andrew Lake or Mary Lake against a different lake.
Verdict
Both lakes earn the same Grade A. The tiebreakers come down to clarity (Andrew Lake: 13.9 ft, Mary Lake: 10.5 ft) and what you want from the lake. Andrew Lake supports more documented fish species.
Source: EPA National Aquatic Resource Surveys, 2026.