Why was fort Pontchartrain built where it was?

The location where Fort Pontchartrain was placed, was on a sandy bluff and afforded a good lookout point. to the south lay small islands including Grosse Isle, and to the north, Belle Isle, before the river opened out to Lake St Claire. Therefore this narrows was a good way to keep tabs on who was coming up and down the river with an unobstructed vantage point. It allowed control over the waterway for Antoine de la Mothe Cadillac and his settlement. (submitted by Denny James-Michigan)

I fully agree, situating the fort on the Michigan side of the river where they did, gave the only logical strategic position obtainable. Could we imagine how backward it would have been to locate the fort on the Ontario side? (submitted by screenmagazine-Michigan)