This map comes from the Washington Post and it uses the American Community Survey to explore languages spoken by Americans at home other than English.
I got stuck (in a good way) on the seemingly random counties of German speakers. After I poked around a bit, I found one where almost 50% of the county speaks German. After some quick investigation, it turns out that Holmes County, Ohio is a centre for the Amish population. The Amish, of course, will often speak German or Pennsylvania Dutch, thus accounting for the abnormally high percentage of German speakers.
Credit for the piece goes to Dan Keating and Darla Cameron.