French Lake vs Union Lake
Water quality, depth, fish species, and recreation comparison.
French Lake reads lower on nutrients and algae than Union Lake. Both are in Rice County, Minnesota.
French Lake and Union Lake are both in Minnesota — a same-state head-to-head where the comparison comes down to lake-specific differences in depth, watershed, and monitoring history rather than the broader state-level water-quality regime. The readings are close: French Lake and Union 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.
French Lake
Very murky, less than 1.7 ft of visibility.
Union Lake
Very murky, less than 3 ft of visibility.
Side-by-Side Metrics
| Metric | French Lake | Union Lake |
|---|---|---|
| Water Clarity | 1.7 ft | 3 ft Better |
| Phosphorus | 134 µg/L Better | 375 µg/L |
| Chlorophyll-a (Algae) | 46.3 µg/L | 29.2 µg/L Better |
| Maximum Depth | 56 ft Better | 10 ft |
| Surface Area | 876 acres | 397 acres |
| Public Access | Yes | Yes |
| Fish Species | 16 Better | 0 |
| Trophic State | hypereutrophic | hypereutrophic |
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.
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Verdict
Union Lake reads lower on nutrients and algae than French Lake. Water clarity: 3 ft vs 1.7 ft. For more fish-species variety, French Lake edges ahead with 16 documented species.
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Where to stay near French Lake and Union Lake
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Source: EPA National Aquatic Resource Surveys, 2026.