Montmagny County Lake Quality
Québec, 2 lakes, average grade B (Good)
Only 2 lakes in Montmagny County carry an active grade. The county-level summary is therefore representative of those specific lakes, not necessarily of every water body in the county. The county-wide average lands at B — solid water quality with most lakes carrying clear summer transparency and low-to-moderate phosphorus.
The county's lakes lean shallow, which makes the grades sensitive to wind, sediment-resuspension, and any nutrient inputs from the watershed. The cleanest lake on the books is Lac Jally (B); the most-stressed is Lac FrontièRe (B).
Quick Answers for Montmagny County
Planning a trip? Check special fishing regulations for Lac Jally — or check the official Québec fishing regulations.
All Lakes in Montmagny County
| Rank | Lake | Grade | Clarity | Phosphorus |
|---|---|---|---|---|
| 1 | Lac Jally | B | 8.9 ft | 8.5 µg/L |
| 2 | Lac FrontièRe | B | 5.2 ft | 17.4 µg/L |
Other Counties in Québec
See how Montmagny County stacks up in the national county water-quality rankings, or browse the full directory of graded lakes across all 38 states.
Where to stay near Montmagny County
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Source: EPA National Aquatic Resource Surveys, 2026.