Basin Maps

Interactive Map

The following map displays the sub-basins that drain into the Lake Ontario-St. Lawrence River system, managed by the International Lake Ontario - St. Lawrence River Board. The coloured circles indicate locations of water level gauges. Click on the Legend, at the top left of the map, for more information. You may also click on any of the coloured circles to obtain information and data from the water level gauge.

View full map

Static Map

Map of Lake Ontario and St. Lawrence River