Park County Lake Quality
Montana, 1 lakes, average grade C (Fair)
Only 1 lakes in Park 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. 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. Nla Lake (C) is the cleanest in the county.
Quick Answers for Park County
Planning a trip? Check special fishing regulations for Nla Lake — or check the official Montana fishing regulations.
All Lakes in Park County
| Rank | Lake | Grade | Clarity | Phosphorus |
|---|---|---|---|---|
| 1 | Nla Lake | C | 5.6 ft | 59.3 µg/L |
Other Counties in Montana
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.
Where to stay near Park County
Top-rated places to stay near Park County
Availability and prices from Stay22 partners (Booking.com, Vrbo, Expedia). We may earn a commission from bookings, at no extra cost to you.
Planning a trip to Park County?
Get lake water-quality report cards plus the best cabin & lodging deals near Park County — straight to your inbox. No spam, unsubscribe anytime.
Source: EPA National Aquatic Resource Surveys, 2026.