In the last half-century, baby-naming has become more susceptible to trendiness:
Last year, a total of 20,791 Emmas were born in the United States. The size of that cohort was only surpassed by the 22,158 Sophias added to the US population in 2012. Together, both names came out on top in 47 of the 50 states. …
Considering the top names for girls per state, we see two distinct blocks emerging: Sophialand is anchored on the West Coast, with 7 of its 16 states forming a contiguous territory, from Washington State all the way down to Texas. Its giant next-door neighbour Emmaland occupies a gigantic swathe of land across the west, ranging unimpeded into Pennsylvania. A few mutual enclaves and exclaves complicate the situation in the Midwestern to Northeastern area: there are four Sophia-enclaves (Illinois, Ohio, Rhode Island and a complex of 5 contiguous states: New York, New Jersey, Delaware, Maryland and Virginia). All the Emma states are contiguous, except for Emmaland’s New England province: Maine, New Hampshire, Massachusetts, and Connecticut. The US’s two non-contiguous states each declare for either of the main nations: Alaska is Emmaland, Hawaii is Sophialand.
Frank Jacobs notes that the boy version of the map is “much more fragmented: 11 names circulate as states favourites, instead of only 5 on the girls’ side” – as seen below: