Sinclair Lewis, writer linked to Wales.
First American to win the 'Nobel Prize for Literature'.
Connection: Of Welsh descent.
I've seen his name on several lists of famous Welsh Americans. I don't know exactly how sound the documentation is, but I think he's probably at least as legit as James Monroe or Andrew Jackson. I read 'Main Street' for the first time last summer and was struck by how much he made think of Kate Roberts.