Like Lake, Hamilton County is a must-win for Obama -- it's the largest of the "Obama-Bush" counties. His strength here helped him win Ohio by 5 percentage points in 2008. Cincinnati is the largest city in Hamilton and the state's third-most-populous, with blacks making up about 26 percent of the population. Obama took the county in 2008, 53 percent to 46 percent, in part due to the strong turnout by black voters. That six-point jump from John Kerry's 2004 showing was the biggest shift among the 13 counties casting at least 100,000 votes in the 2008 election. With polls showing enthusiasm waning compared with 2008, especially among Democrats, success for Obama here depends on turnout, specifically in the black community. Some pundits, including Bloomberg's Matthew Dowd, who was part of Bush's campaign team, predicted that whoever wins Hamilton County will win the state -- and the election.
Left: Obama greets supporters after speaking at a campaign event at Eden Park in Cincinnati on Sept. 17, 2012.