The fight for the national political battleground is an expensive one.
With just a month left before the election, the two presidential campaigns and outside supporters already have spent more than $110 million on TV advertising in Ohio.
That's about a sixth of all national spending to that point.
Both the president and Mitt Romney have made frequent stops in the state.
No Republican has won the White House without carrying Ohio, and the last president elected without winning Ohio was Democrat John F. Kennedy in 1960.