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.

TAMPICO, ILLINOIS - A mural of 40th President of the United States Ronald Reagan and First Lady Nancy Reagan is across the street from the Ronald Reagan Birthplace and Museum building in Tampico, Illinois on Saturday April 14, 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)