L'Anse aux Meadows in Newfoundland was only sporadically occupied by small numbers of Vikings, but we at least have the remains of building foundations and a few other artifacts.
Are you aware of anything in the Great Lakes area that can't be easily explained away by current archaeological theories?
Most of the artifacts in North America which were suggestive of PreColumbian transoceanic contacts (PCTC for the duration of this message)have only survived as photos or drawings, because there has been such a strong bias against PCTC for over a century now. You’ve probably heard the story of the barge full of unacceptable artifacts and finds which the Smithsonian had towed out into the Atlantic a ways and dumped. It’s a tactic more familiar to historians of the rise of the Third Reich or Pol Pot. Like the recent debt ceiling / budget struggle, it was a political act.
The earliest peopling of the Americas used to be dated at about 1000 BC at the earliest. There was resistance to this idea, due to the massive diversity (particularly south of the Rio Grande) in language, culture, architecture, and written language. Louis Leakey, as a visiting lecturer, was probably as responsible as anyone for breaking down the resistance to the silly notion that humans had only been in the Americas for 3000 years. His Calico site dig didn’t establish what he thought it did, though.
The Clovis “revolution” grew out of a range of finds which tended not to be found in stratified contexts (that is, a series of stone artifact styles, found one on top of the other, in any one site, showing a long habitation), but it pushed back the human presence in North America some thousands of years. There wasn’t an exact date, just estimates based on depths of the finds, and other estimates of the length of time it might take for these different knapping techniques to develop and succeed previous styles. The 1000 BC date was still clung to like grim death by those who flat-out rejected any estimated dates for the artifacts.
The scientific dating of the Clovis artifacts (which later became the oldest acceptable strata) was finally accomplished after 1950, using radiocarbon (obviously the ancient campfire sites around which the stone artifacts were found), and pushed back human habitation by at least 9000 years. That became the new glass floor, beneath which dates could not fall. That’s been broken down by Topper in North America, and by Monte Verde in S America.
Back on topic — One of the lost (probably destroyed, but it might someday emerge somewhere on the U of M campus where it was taken) inscription stones was found up by Petoskey I think, otherwise east of there, near the shoreline. Whatever the context was, and the artifact itself, is gone, although the general findspot is known.
Other info has emerged in recent years regarding the copper — the trade networks in the PreColumbian Americas were far-reaching, and upper peninsula copper has (AFAIK) been found in South- and Central American PreColumbian contexts. It may have got there step by step, hand to hand — the usual ex cathedra claim — but I think that idea is fairly insulting to the capabilities of PreColumbian Americans.
Regardless, it doesn’t exactly mitigate against copper trafficking across the Atlantic in ancient times, now does it? :’)
There’s another Barry Fell anecdote, maybe in one of the books (if not, in ESOP), in which he notes that the first evidence of PreColumbian contact comes from Columbus himself — on one of the islands visited on the first voyage, an old guy was wearing a shiny object as the dangler on a necklace. The geezer said he’d found it when a young man, while diving (for fish, mussels, or whatever) and had kept it since. Columbus or someone with him drew a likeness of the coin, which likeness is preserved, and it appears to have been a Phoenician coin — something Columbus would have known zero about.