There's been many recent threads on Vinland, such as this and this recent threads about Vinland.

The short answer here is we don't know exactly where Vinland is -it's a specific place in the Vinland Sagas, not the entire North American continent, nor do we know if they actually encountered any natives there. But the locations that have been suggested for Vinland are all south of Newfoundland, which is the southernmost spot in North America we know Vikings visited.

Vikings absolutely did not meet the Thule Culture in Vinland because the Thule Culture had barely come into existence in Alaska during the Viking Age, and would never spread to anywhere near Vinland. The Thule culture did over the centuries advance to Greenland, where it's likely there are records of Scandinavians interacting with 'Skræling' natives as late as around 1400, which is likely the Thule people. This is 400 years after the events of the Vinland Sagas and not the Viking Age though.

If Vikings ran into natives in Newfoundland or farther south in the Bay of Saint Lawrence or Nova Scotia, it'd have been some Algonquin people, possibly ancestors of the Beothuk.