Adair County Lake Quality
Wisconsin, 5 lakes, average grade D (Poor)
Only 5 lakes in Adair 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. On average, Adair County lakes grade D, with phosphorus loading and reduced clarity showing up across most of the dataset.
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 Mormon Trail Lake (C); the most-stressed is Greenfield Lake (F).
Quick Answers for Adair County
Planning a trip? Check special fishing regulations for Mormon Trail Lake, whether the fish are safe to eat, and the best times to fish — or browse the full Wisconsin regulations index.
All Lakes in Adair County
| Rank | Lake | Grade | Clarity | Max Depth | Phosphorus |
|---|---|---|---|---|---|
| 1 | Mormon Trail Lake | C | 6.2 ft | - | - |
| 2 | Nodaway Lake | D | 2.8 ft | - | - |
| 3 | Greenfield Lake | F | 2.1 ft | - | - |
| 4 | Meadow Lake | F | 1.7 ft | - | - |
| 5 | Lake Orient | F | 1.3 ft | - | - |
Source: EPA National Aquatic Resource Surveys, 2026.