I cannot authenticate what I am about to say and I blame no one if they disbelieve it. It is taken from memory.
Several years ago we clipped out of a newspaper a story where archaeological evidence was supposedly found showing the Vikings tied their ships to islands, now buttes, in the Turtle Mountains of ND and Manitoba. At that time much of ND was a lake that was supposedly connected through other waterways to the Atlantic.
Interesting, that’s new to me.
off the coast of Maine on Monhegan Island (or rather the small island right next to it) there is a rock with supposedly Viking writing on it. Maybe if you look real close.
Monhegan is a logical place for it though, its the first place that europeans seem to have landed in the area, and it was, back in the day, overun with cod, the key reason to be there.
The old glacial lakes (Souris and Agassiz) drained long before the Vikings would have come through.