In the Upper Midwest encompassing more than three dozen counties along or adjacent to the Mississippi River. In 2016, the American voters in these districts shifted, in some cases dramatically, to the GOP nominee after backing Democratic presidential nominees in at least six consecutive elections. In eight of the counties, voters had picked Democrats at least 10 elections in a row before backing Donald Trump for President.

AUSTIN, MINNESOTA - Austin is the home of Hormel Foods, visitors tour the Spam Museum where exhibits explain the history of the Spam products in American history and around the world in Austin, Minnesota on Tuesday April 10, 2018. In 2016 in the Upper Midwest encompassing more than three dozen counties along or adjacent to the Mississippi River American voters in these districts shifted, in some cases dramatically, to the GOP nominee after backing Democratic presidential nominees in at least six consecutive elections. In eight of the counties, voters had picked Democrats at least 10 elections in a row before backing Donald Trump for President. (Photo by Melina Mara/The Washington Post via Getty Images)