Oregon County Lake Quality
Wisconsin, 1 lakes, average grade A (Excellent)
Only 1 lakes in Oregon 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's average grade is A — among the cleanest in Missouri. 1 lakes pull an A on their own, and almost none fall into the D or F brackets.
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 Mccormack Lake (A); the most-stressed is Mccormack Lake (A).
Quick Answers for Oregon County
Planning a trip? Check special fishing regulations for Mccormack Lake, whether the fish are safe to eat, and the best times to fish — or browse the full Wisconsin regulations index.
All Lakes in Oregon County
| Rank | Lake | Grade | Clarity | Max Depth | Phosphorus |
|---|---|---|---|---|---|
| 1 | Mccormack Lake | A | 11.7 ft | - | 6 µg/L |
Source: EPA National Aquatic Resource Surveys, 2026.