Park County Lake Quality
Wyoming, 21 lakes, average grade C (Fair)
Park County's 21 graded lakes fall in the moderate-density bracket for {{stateName}}. The county-level average smooths over real differences — a single agricultural watershed near the southwest corner can pull the average down even if the rest of the county runs clean. Park County averages to a C. The distribution behind that average matters more than the letter: a few stressed lakes versus many decent ones can produce the same average as the inverse.
Most of the county's monitored lakes are shallow — under 50 feet — which means wind keeps the water column mixed all summer and sediment-bound phosphorus releases back into the surface layer whenever the bottom is disturbed. West Newton Lake (A) is the cleanest in the county.
Quick Answers for Park County
Planning a trip? Check special fishing regulations for West Newton Lake — or check the official Wyoming fishing regulations.
All Lakes in Park County
| Rank | Lake | Grade | Clarity | Phosphorus |
|---|---|---|---|---|
| 1 | West Newton Lake | A | 17.7 ft | - |
| 2 | Lower Sunshine Reservoir | A | 10.6 ft | 10 µg/L |
| 3 | Upper Sunshine Reservoir Lpd | B | - | 20 µg/L |
| 4 | Upper Sunshine Reservoir Rtpd | B | - | 20 µg/L |
| 5 | Deaver Reservoir -D | B | - | 20 µg/L |
| 6 | Hogan Reservoir | B | - | 20 µg/L |
| 7 | Tippecanoe Reservoir -D | B | - | 20 µg/L |
| 8 | Buffalo Bill Reservoir Transitional Littoral | C | - | 50 µg/L |
| 9 | Buffalo Bill Reservoir Lacustrine Pelagic | C | - | 55 µg/L |
| 10 | East Newton Lake D | C | - | 40 µg/L |
| 11 | Nla Lake | C | 6 ft | 22000 µg/L |
| 12 | Nla Lake | D | 9.8 ft | 126.9 µg/L |
| 13 | Buffalo Bill Reservoir Lacustrine Littoral | D | - | 60 µg/L |
| 14 | Buffalo Bill Reservoir Transitional Littoral | D | - | 65 µg/L |
| 15 | Buffalo Bill Reservoir Transitional Pelagic | D | - | 70 µg/L |
| 16 | Buffalo Bill Reservoir Riverine Littoral | D | - | 60 µg/L |
| 17 | Buffalo Bill Reservoir Riverine Littoral | D | - | 65 µg/L |
| 18 | City Reservoir | D | - | 65 µg/L |
| 19 | Buffalo Bill Reservoir Transitional Pelagic | D | 2.8 ft | 70 µg/L |
| 20 | Beck Lake D | F | - | 90 µg/L |
| 21 | Buffalo Bill Reservoir | F | - | 95 µg/L |
Other Counties in Wyoming
See how Park County stacks up in the national county water-quality rankings, or browse the full directory of graded lakes across all 34 states.
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Source: EPA National Aquatic Resource Surveys, 2026.