The excavation of the site at L'Anse aux Meadows in the 1960s gave a defintie evidence that Scandinavians of the Viking Age had gone to North Amercia beyond Greenland. Prior to that, the evidence was limited to the Vinland Sagas and Adam of Bremen (whose account is a likely influence on the sagas) and therefore the credibility rested entirely on their credibility, which was at something of a historic nadir at that point, as /u/platypuskeeper (i.e. me but a bot will complain if I don't give credit) elaborated on in this post.

Today we have further evidence of Norse-Inuit contact in the later Middle Ages, and possible visits to Baffin Island and the Labrador coast. (Thought to be the Helluland and Markland of the Vinland Sagas) Through the somewhat controversial archaeological work of Patricia Sutherland. At the same time there have been expeditions by Mats G Larsson to look for Norse sites south of L'Anse, without much result.