Seneca Lake and Cayuga Lake are close enough in size that arguing about it is a local sport. The chart polygons put them at 174.6 and 172.6 square kilometers, two square kilometers apart. Oneida Lake is a different proposition at 206.4 square kilometers, wide open and quick to build a chop once the wind has a fetch across it. North of all of that sits Lake Champlain at 1,116.6 square kilometers, which is more water than the next fourteen named lakes in this pack put together. Then there is everything else: Lake George, Great Sacandaga Lake, Chautauqua Lake, Raquette Lake, Cranberry Lake, Black Lake, and several thousand smaller waters that most charts treat as scenery.
The pack carries 6,569 charted water bodies. 3,614 of them are named, which is the fifth largest named count among the 48 state lake packs, and 334 of those named lakes are over a square kilometer, which ranks sixth. The outlines come from the National Hydrography Dataset. The depth on them is built from state elevation surveys, which is the reason a reservoir arrives on the screen as charted water you can plan a route across against your draft instead of a blue shape with a name floating in the middle of it.
The 6,569 charted water bodies rank 14th of the 48 state packs. That is the least interesting of the three numbers. Counting water bodies rewards a state for having a lot of small ponds in it, and every state in the northeast has those.
The other two counts are the ones worth reading. 3,614 of these waters carry a name, fifth of 48. 334 named lakes measure over a square kilometer, sixth of 48. That second figure is closer to counting places you can put a boat in and actually run it somewhere, and on that measure this pack sits in the top six in the country.
A little over half the water in the pack, 3,614 of 6,569, has a name attached to it. That share is what lets you type in the pond somebody told you about at work and get the pond, rather than scrolling a map hunting for the right shape.
| Lake | Charted surface area |
|---|---|
| Lake Champlain | 1,117 km² (275,917 acres) |
| Oneida Lake | 206 km² (51,002 acres) |
| Seneca Lake | 175 km² (43,145 acres) |
| Cayuga Lake | 173 km² (42,650 acres) |
| Lake George | 115 km² (28,392 acres) |
| Great Sacandaga Lake | 85 km² (20,979 acres) |
| Chautauqua Lake | 54 km² (13,220 acres) |
| Allegheny Reservoir | 49 km² (12,133 acres) |
| Keuka Lake | 47 km² (11,589 acres) |
| Canandaigua Lake | 42 km² (10,453 acres) |
| Skaneateles Lake | 35 km² (8,723 acres) |
| Cranberry Lake | 35 km² (8,575 acres) |
The twelve largest named lakes the New York pack carries, by charted surface area, measured from the chart polygon itself. The pack carries 6,569 charted water bodies in all, 3,614 of them named, and 334 named lakes larger than one square kilometer.
There is no NOAA chart for a reservoir. NOAA surveys salt water and the navigable rivers, and a lake held behind a dam up a valley in the Catskills is outside all of it. Inland depth in Helm is built from state elevation surveys instead, and the water bodies themselves come from the National Hydrography Dataset. Those two sources together are the whole reason a reservoir is charted water in Helm, with contours on it and a depth number you can read against your own draft.
A reservoir also sits at whatever level it is being held at, and that is the thing to keep in your head while reading a contour on one. Pepacton Reservoir at 23.0 square kilometers and Ashokan Reservoir West Basin at 20.8 are city water supply, so the level they are holding in October was a decision somebody made rather than something the weather did. Stillwater Reservoir at 25.1 square kilometers and Allegheny Reservoir at 49.1 work the same way.
A surveyed contour is tied to the surface elevation on the day the survey was taken. When the pool is being held below that, the water under you is shallower than the contour reads, by the difference. The first place it shows is the shoulder of the old creek channel, in a cove, at idle speed. Helm carries the survey date beside the reading and shades the water your draft cannot cross, which is the part that gets your attention while you still have room to turn.
Lake Champlain is the biggest thing in the pack by a wide margin, at 1,116.6 square kilometers, or 275,917 acres. It covers more water than the next fourteen named lakes here added together. The packs are cut to a box rather than to a state line, so Champlain sits in this pack and in the Vermont pack, and either one gives you the whole lake instead of a chart that stops out in the broad lake. Allegheny Reservoir at 49.1 square kilometers works the same way down in the southwest corner, as does Charleston Lake at 26.3, which the box picks up north of the river.
After Champlain there is a long step down and then a fairly even run.
Oneida Lake at 206.4 square kilometers is the largest of the rest, and the only one besides Champlain over 200. Seneca and Cayuga are two square kilometers apart, close enough that the answer changes with the water level and with who is asking. Lake George at 114.9 square kilometers is about 30 square kilometers larger than Great Sacandaga Lake at 84.9. Below that the sizes come down in small steps: Chautauqua Lake at 53.5, Allegheny Reservoir at 49.1, Keuka Lake at 46.9, Canandaigua Lake at 42.3, Skaneateles Lake at 35.3.
3,614 named waters is a lot of labels, and the labels settle an argument the words in them do not. Raquette Lake measures 21.6 square kilometers, 5,337 acres. Raquette Pond, a separate water body in the same pack, measures 21.0 square kilometers, 5,189 acres. Six tenths of a square kilometer between the two of them. Whatever the word pond is doing in that name, it is not telling you anything about the size, and 5,189 acres has enough fetch on it to build a chop no matter what the sign at the ramp says.
The pattern holds further down the list. Cranberry Lake at 34.7 square kilometers and Black Lake at 31.6 are both larger than Owasco Lake at 27.2, which is the one most people would name first. Skaneateles Lake at 35.3 is smaller than Chautauqua Lake at 53.5 and larger than Pepacton Reservoir at 23.0. None of that reads off a map with no figures on it, and it is the kind of thing that decides how early you leave the ramp.
Inland lake depth comes from state elevation surveys rather than from nautical charts, and a reservoir sits at whatever level it is being held at that week. Treat the shape and the depth as a guide, keep a lookout, and verify locally.
Depth data. Seneca Lake at 174.6 square kilometers, Cayuga Lake at 172.6, Keuka Lake at 46.9, Canandaigua Lake at 42.3, Skaneateles Lake at 35.3 and Owasco Lake at 27.2 all come in as charted water with contours on them. The outlines come from the National Hydrography Dataset and the depth is built from state elevation surveys, and each reading carries the date of the survey behind it.
The packs are cut to a box rather than to a state line, so all 1,116.6 square kilometers of Lake Champlain are in this pack, and in the Vermont pack as well. Downloading either one is enough for a run up the broad lake. Champlain is the largest water this pack carries by more than five times over Oneida Lake, the next one down at 206.4 square kilometers.
A contour is tied to the surface elevation on the day of the survey, so when the pool is being held lower than that, the water under you is shallower than the contour reads by that difference. Check what level the reservoir is holding before you tow, then read the chart against it. Pepacton Reservoir is 23.0 square kilometers in this pack and Stillwater Reservoir is 25.1. With your draft entered, Helm shades the water your boat cannot cross and reports the shallowest point along any line you draw, which on a drawn down reservoir is the shoulder of the old creek channel rather than the middle of it.
Helm Boating