I love maps, especially maps that present data in unusual ways. I used to follow Strange Maps, an awesome little web site that collect odd and unusual maps from around the world. (Sadly, they moved to a bigger website and it's harder to navigate, which is the link above, so I only go there occasionally.)
Anyway, from a different source, here's a link to a map of the most common baby names in America today. I'm not going to reproduce the maps; you can go there and look.
On the girl side, there's not much to look at. I'm always sad when I see how little variation there are in names. Names are a personal thing, and it sucks when you get to elementary class and you have to be referred to as "Emma C." Emma M." and "Emma T." I don't know what on earth is up with Vermont and Idaho; I guess they just have their own ideas as to how their classrooms will look in about five years. (For the record, Olivia sounds like a basic cable talk show host and Eva sounds like the nicest person at the DVM.)
Thankfully, for the boys, things are a lot more diverse. It's still irritating that Liam is so popular in the Rocky Mountains (there are apparently people who somehow think that it's easy to mistake Wyoming for Ireland) but the rest of the nation plays it safe with a lot of Jims, Michaels, and Jakes. I'm actually a little surprised that the South stuck by the standard William; I assumed it would be Jefferson or Rascal or Starsnbars.
Still, I'm baffled how things like this happen. Clearly the South likes William and the Mid-Atlantic likes Michael...but why? William a pretty standard name, so what makes the west pick it out amongst the others? My assumption is that there is some regional reason, like there was a kickass governor names William or some sports star who was Jake, but I think it's just one of those odd sociological things that happens. People know people who name their kids something, and then it slowly gets passed around person to person until an entire region trends towards it. I wonder if social media will eventually erode this away?