Lakes / New York / Tomhannock Reservoir
Tomhannock Reservoir, New York
1,720 acres
Surface Area
50 ft
Max Depth
23 ft
Average Depth
19 mi
Shoreline
388 ft
Surface Elevation
Where It Sits, and How Deep It Goes
Locator - New York
42.84 degrees N, 73.54 degrees W - Rensselaer County. State and county outlines drawn from Census boundary data; the lake marker is placed by its New York State DEC coordinates, not by eye. Schematic - not a survey map.
Depth Profile - Tomhannock Reservoir
Schematic cross-section drawn to one shared depth scale - not a survey or bathymetric map.
How Tomhannock Reservoir Stacks Up
- The largest lake in Rensselaer County among those counted.
- Its average depth of 23 ft is more than 2 times a typical shallow New York lake, which averages under 10 ft.
- About 17 miles from Albany, as the crow flies.
- 20 fish species on the DEC list for this lake.
Fish Species
WalleyeSmallmouth BassLargemouth BassBlack CrappieBluegillPumpkinseedYellow PerchRock BassBluntnose MinnowBrown BullheadChain PickerelCommon CarpEmerald ShinerFallfishGolden ShinerSpottail ShinerTessellated DarterWhite PerchWhite SuckerYellow Bullhead
Species recorded for this lake. Presence only - no abundance ratings.
Facts and Figures
Waterbody ID50524095
CountyRensselaer
Coordinates42.8424, -73.5425
Deepest Natural Lakes in New York
| # | Lake | County | Surface Area | Max Depth |
|---|---|---|---|---|
| 1 | Seneca Lake | Ontario, Yates, Seneca, Schuyler | 43,343 acres | 618 ft |
| 2 | Cayuga Lake | Cayuga | 42,956 acres | 435 ft |
| 3 | Skaneateles Lake | Onondaga, Cortland, Cayuga | 8,960 acres | 300 ft |
| 4 | Canandaigua Lake | Ontario, Yates | 10,558 acres | 276 ft |
| 5 | Lake George | Essex, Warren | 28,451 acres | 187 ft |
Largest Lakes in New York
| # | Lake | County | Surface Area | Max Depth |
|---|---|---|---|---|
| 1 | Lake Erie | Erie | 6,360,010 acres | - |
| 2 | Lake Ontario | Jefferson | 4,656,925 acres | - |
| 3 | Lake Champlain | Washington | 277,117 acres | - |
| 4 | Oneida Lake | Oswego | 51,324 acres | - |
| 5 | Seneca Lake | Ontario, Yates, Seneca, Schuyler | 43,343 acres | 618 ft |
Sources: New York State DEC lake data (ID 50524095); USGS. Verified October 30, 2026.