I was reading in another subreddit, and someone said how growing up near the lakes was nothing like seeing the sea for the first time. It got me thinking; did the Europeans realise it was lakes (Either through knowledge of the Pacific, Natives or other means.) Or did they believe they had reached the Pacific itself. Any sources or primary evidence on this as well?
It wouldn't take much for the French (first Europeans to discover the Great Lakes) to realize it was a lake instead of a sea, just take a sip of the water. Do not forget that French did trade, fight, and interact with Indians around the great lakes. Matter of fact, Huron was the first lake discovered and Erie surprisingly last by Europeans. The reason was because the Iroquois were so dominate in the Lake Erie region as to make traveling overland to explore initially easier and safer.
Joseph Le Caron was the Franciscan Friar who was the first European to discover Lake Huron. He was sent as a missionary and was looking for the Huron's tribe main village. French probably heard rumors of these huge fresh water lakes from interactions with Native Americans before they ever set sight on them. This website has a good transcription of the History of the Great Lakes. source