I used to live in Central Illinois -- in Decatur, which is 40 miles from Springfield, and just a few miles from the homestead where Abraham Lincoln settled when he first arrived in Illinois, as a 21 year old.
So for me, the most remarkable facet on Daniel Day-Lewis’s portrayal of Abraham Lincoln was the accent. He sounded exactly like some of the people I knew Downstate -- and more than a little like Gov. Jim Edgar, who acquired his accent by growing up in Charleston, where his family has lived so long that one of his ancestors saw Lincoln debate Douglas there.
Day-Lewis is well known for the research he does on his accents. To play Bill the Butcher, the 19th Century gang leader in Gangs of New York, he listened to what is reputedly the only recording of Walt Whitman, the Brooklyn-born poet.
Those three states and the counties of those states all have very particular sounds. The national archive, although there are no contemporary recordings obviously, there are some early recordings from the turn of the century.