What is the St source or headwater?

The St. Lawrence River's source or headwater can be traced back to Lake Superior, North America's largest freshwater lake by surface area. Lake Superior is located at the westernmost end of the St. Lawrence River system and is fed by numerous rivers and streams, some of which originate from melting glaciers and snowfields. The waters from Lake Superior flow through a series of Great Lakes and connecting channels before eventually converging into the St. Lawrence River. Therefore, Lake Superior serves as the ultimate headwater or source of the St. Lawrence River.