Jarl (Earl) Henry Sinclair is alleged to have sailed to America in 1398 or so. In his party was Sir James Gunn. There is a stone carving in Westford, Massachusetts that depicts the Clan Gunn crest.
https://museum.westford.org/the-westford-knight/
The Micmaq Indians have legends of an encounter with someone, possibly Sinclair.
http://www.clansinclairsc.org/images/Prince%20Henry%20Sinclair%20Brochure.pdf
https://www.rockartmuseum.com/the-legend-of-glooscap/
The Scottish Discovery of America
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History of the Prince Henry Sinclair - Sir James Gunn Voyage
https://jamesonfamily.org/Sinclair_Gunn.html
Also, check out the Zeno Narrative:
http://www.orkneyjar.com/history/historicalfigures/henrysinclair/princehenrytrip.htm