Marion County Lake Quality
Tennessee, 3 lakes, average grade C (Fair)
Only 3 lakes in Marion 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 average is C — the middle of the rubric, with one or two lakes pulling the average up or down depending on year.
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 (B) is the cleanest in the county.
Quick Answers for Marion County
Planning a trip? Check special fishing regulations for Nla Lake — or check the official Tennessee fishing regulations.
All Lakes in Marion County
| Rank | Lake | Grade | Clarity | Phosphorus |
|---|---|---|---|---|
| 1 | Nla Lake | B | 6.7 ft | 41.3 µg/L |
| 2 | Tennessee River Lake | C | 7.6 ft | 35.8 µg/L |
| 3 | Tennessee River Lake | C | - | 38 µg/L |
Other Counties in Tennessee
See how Marion 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 Marion County
Top-rated places to stay near Marion 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 Marion County?
Get lake water-quality report cards plus the best cabin & lodging deals near Marion County — straight to your inbox. No spam, unsubscribe anytime.
Source: EPA National Aquatic Resource Surveys, 2026.