The word “esker” comes from the Gaelic word eiscir
, or ridge. An esker is a ridge of sand and gravel deposited onto the land surface by a river flowing beneath a glacier. The Brampton Esker was formed approximately 10,000 years ago during the last advance of the Lake Ontario Lobe of the Laurentide Ice Sheet. The Brampton Esker is about eight kilometres long, two kilometres wide and up to 50 metres thick.