On assignment for The Atlantic, correspondant Graeme Wood travels to Hibbing, thinking he might discover the origins of Bob Dylan's particular accent. What he gets is an earful, but not of what you might think.
In truth, Sarah Palin has more of a Minnesota accent than Dylan does.
Dylan sure doesn't sound like the Minnesotans I know, and not the northern Minnesotans I know. I moved here, so I can here the various types of Minnesota accents better than somebody from here. We have a relative from Austin, MN who sounds just a wee bit southern. Dylan must have hung out with some people from somewhere else.
I'd read that Bob Dylan actually modelled his voice after the voice of Woody Guthrie. According to the story, Dylan met Guthrie in the late 1950s. Guthrie was a native Oklahoman and sang and spoke with a distinct twang. By the time Dylan met him, Guthrie was coping with Huntington's disease, which further extended his Oklahoma drawl. The story concluded that as a Guthrie protégé, Dylan imitated Guthrie from that point forwards.
So it's very likely Dylan's twang didn't originate on the Iron Range, but instead with his mentor, Woody Guthrie.