Depth
Lake Ontario (Lake America) Depth Map
Lake Ontario's deepest point sits in the Rochester Basin, west of Oswego, at 802 feet.
At 802 feet (244 meters), Lake Ontario's maximum depth is in the Rochester Basin, west of Oswego. That depth is a large part of why the lake rarely freezes over completely and why surface water temperature can drop fast when wind pushes warm surface water offshore.
The bathymetry layer on the map above is a placeholder until a public depth-contour tile source is wired in. The 802 foot figure and its location are the two facts this page can state with a source today.
Source: Britannica, NOAA bathymetry chart