Sheridan County Lake Quality
Wyoming, 6 lakes, average grade B (Good)
Sheridan County has 6 graded lakes — a thin enough sample that one or two stressed lakes can move the county average noticeably. Use the per-lake pages below for what actually matters. 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 Twin Lakes Reservoir D (A); the most-stressed is Mavrakis Pond (D).
Quick Answers for Sheridan County
Planning a trip? Check special fishing regulations for Twin Lakes Reservoir D — or check the official Wyoming fishing regulations.
All Lakes in Sheridan County
| Rank | Lake | Grade | Clarity | Phosphorus |
|---|---|---|---|---|
| 1 | Twin Lakes Reservoir D | A | - | 10 µg/L |
| 2 | Kleenburn Pond | A | 11.5 ft | 15 µg/L |
| 3 | Park Reservoir | B | 10.8 ft | - |
| 4 | Sawmill Reservoir D | B | - | 20 µg/L |
| 5 | Sibley Lake | B | 9.2 ft | 20 µg/L |
| 6 | Mavrakis Pond | D | 0.9 ft | 50 µg/L |
Other Counties in Wyoming
See how Sheridan County stacks up in the national county water-quality rankings, or browse the full directory of graded lakes across all 34 states.
Where to stay near Sheridan County
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Source: EPA National Aquatic Resource Surveys, 2026.