Was looking at the swing map for 2012. Looks like many Southern Ohio counties (particularly in the South-Central part) swung to Obama, while the opposite was true of most of Northern Kentucky. However, Southern Ohio was traditionally more Republican than Northern Kentucky. In 1896, for example, McKinley won the Southern Ohio counties, while Northern Kentucky was Bryan country.
While checking the ancestry stats, I found that Adams County, OH has twice the amount of (self-reported) German ancestry (about 21%) as Lewis County, KY (10%) - even though they border each other. Looks like the Ohio River was a dividing line in that regard.
Furthermore, Lewis County has more residents of English and "American" ancestry than Adams County. Ancestrally Democratic counties with a lot of "American" ancestry have been trending hard R in recent years.
Also of interest: both Southern Ohio and Northern Kentucky have a
lot of "Unclaimed" residents in terms of religion. White evangelicals are a distant second in both regions.
Anyway, just some observations of mine.