I'd say that yes, definitely, there is a popular perception that American folk music, and even rural music in general, is synonymous with the South, but that's not necessarily the truth of the matter. Clifford Murphy in "The Diesel Cowboy in New England," (Journal of American Folklore, 2014) wrote about growing up as a musician in New Hampshire that "it felt, to me and my peers, as though our corner of the world was one that had largely been without music for much of its long history. My studies since then have shown this to be embarrassingly false." I've personally known people who have felt that southern folk music was seen as the norm in the media as well.

Sandy Ives wrote in "Maine-Maritimes Folklore: The Lumberwoods Connection" about something he referred to as "the northern tradition," which was a pattern of broadside ballads found from Newfoundland south to Northern New Hampshire/Vermont/New York, and across the upper midwest to Minnesota and Ontario. That would argue for a similarity in folk music between the Northern US and Canada. However, Ives also mentioned a dividing line in Maine going from Mt. Washington (in New Hampshire) to Calais, which divided the Maritime from the New England song repertoire.

G Malcolm Laws writes that more British Broadside ballads were found in the Northern US and in the Canadian Maritimes than in the South (which had a lot of the Child Ballads). This has to do with immigration patterns, where Northeastern North America had more immigrants from across the pond at a later date.

Of course, I'm talking historically here. Today, I suspect many people learn songs from different regions. In general, I think probably Northern US folk songs have a similarity to the Canadian ones, but most people aren't aware of that because when they think of American folk music, they think of the south.