Lake Ontario

Lake Ontario is a body of water in Ontario, Canada, and New York, United States, spanning nearly 19,000 square kilometers with an average depth of 86 meters (282 feet). The deepest point reaches 244 meters (800 feet), and it forms an important part of the Great Lakes system in North America.

The basin formed roughly 11,000 years ago when a small stream expanded through glacial movements and created the current shape of the lake. European exploration began in the 17th century as French explorers mapped the waterways.

The name comes from the Huron language and means great lake, as the water once formed a border between Huron territories and lands held by the Iroquois Confederacy. Today, residents use shoreline areas for recreation and smaller communities along the coast maintain maritime traditions.

The Welland Canal connects the water to Lake Erie and allows ships to navigate between different water levels through a lock system. Waterfront promenades in different cities offer access to the shore and work well for walks in all seasons.

One quarter of the Canadian population lives within the watershed, which covers over 64,000 square kilometers of surrounding territory. Despite its size, it is the smallest of the Great Lakes by area and volume.

Location: Ontario

Location: New York

Elevation above the sea: 74.1 m

Part of: Great Lakes, Canada–United States border

GPS coordinates: 43.72889,-78.10639

Latest update: December 4, 2025 14:20