at the risk of seeming very obvious ...
And I'm sure you already know about this but I'll point it out just in case:
The Social Security Administration has top 100 name lists for each state beginning in 1960. Those earlier pre-internet lists might give you an idea of how names vary in popularity according to region/state. A lot of French male names not only in Louisiana, as CKE mentioned, but in places like Vermont and Maine, where there is a sizable French-Canadian population.
Here in Delaware, among old men, there seems to be a disproportionate number of Laytons. To old to be on the SSA's lists, anyway. Oftentimes it's actually a cliche used in funny "How to know if you're a Delawarian" type books/websites. No idea why Layton was so popular.
For the ladies, the cliche name is Margaret Ann, pronounced slurred together like Margurdann. A friend of mine actually has three great-aunts on different sides of his family named that. One went by the full name, one by Marg, and one by Martannie. Oh wait, there was actually a fourth one, but she was always called Tootsie.
Of course Margaret Ann is probably as common as dirt all over the country, but it seems especially so around here. In Oklahoma, where I grew up, the closest thing was Norma Jean.
Before you criticize a man, walk a mile in his shoes. That way, when you criticize him, you're a mile away and you have his shoes!
Steve Martin