Cortland County Lake Quality
New York, 4 lakes, average grade B (Good)
Cortland County has 4 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 Song Lake (A); the most-stressed is Ellis Lake (C).
Quick Answers for Cortland County
Planning a trip? Check special fishing regulations for Song Lake — or check the official New York fishing regulations.
All Lakes in Cortland County
| Rank | Lake | Grade | Clarity | Phosphorus |
|---|---|---|---|---|
| 1 | Song Lake | A | 15.4 ft | - |
| 2 | Upper Little York Lake | B | 11 ft | - |
| 3 | Tully Lake | B | 11.9 ft | - |
| 4 | Ellis Lake | C | 7.8 ft | - |
Other Counties in New York
See how Cortland County stacks up in the national county water-quality rankings, or browse the full directory of graded lakes across all 15 states.
Where to stay near Cortland County
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Source: EPA National Aquatic Resource Surveys, 2026.