As a casual geographer (I've seen a map or two in my day), I can't help but notice that Eastern Russia practically touches what is now known as Alaska, and pre-industrial Tudor superpowers like Japan and China are also pretty close to the the US.
Was Leifur Eiriksson the first man to place America on the map?
I'm also interested if anybody discovered it between Leifur Eiriksson's discovery and Colombus' "discovery".
First, see my comments to /u/machine1a4 if you haven't already. Shaking the Magic-8 Ball of Archaeological Consensus, here's the summary:
One he missed however falls into the "It Is Certain" category. The Yupik, living on both sides of the Bering Strait, made frequently voyages between Asia and North America in historic times (hindered only by the Cold War), and we have every indication that their ancestors made similar voyages long before Columbus or the Norse reached the Americas, maintaining local trade contacts on both continents.
And, of course, it should go without saying that, the failed Solutrean hypothesis not withstanding, the Americas were discovered by a few different waves of people from northeast Asia over many thousands of years. The descendants of those early Americans would have been the first to map the territory.