Sullivan County Lake Quality
Tennessee, 2 lakes, average grade B (Good)
Sullivan County has 2 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. With an average grade of B, Sullivan County sits comfortably above the {{stateName}} median.
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 South Fork Holston River Lake (A); the most-stressed is Nla Lake (C).
Quick Answers for Sullivan County
Planning a trip? Check special fishing regulations for South Fork Holston River Lake — or check the official Tennessee fishing regulations.
All Lakes in Sullivan County
| Rank | Lake | Grade | Clarity | Phosphorus |
|---|---|---|---|---|
| 1 | South Fork Holston River Lake | A | - | 13.8 µg/L |
| 2 | Nla Lake | C | 10.3 ft | 13000 µg/L |
Other Counties in Tennessee
See how Sullivan 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 Sullivan County
Top-rated places to stay near Sullivan County
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Source: EPA National Aquatic Resource Surveys, 2026.