We had another recent question on this topic a few hour ago (was there something in particular that inspired you question, or is it just coincidental?). People in mainland Europe knew about Vinland as early as seventy years after the Norse arrived there (probably sooner, but that's the earliest written record of Vinland we currently have). It's also important to remember that the Norse were only in a small part of a North America for a very brief amount of time. They only established short-lived temporary outposts in Newfoundland before heading back home to Greenland.