Sara P. let us know about a map at National Geographic that shows the distribution of surnames in the U.S.

The names are color coded by region of origin of the name:

A note on methodology: geographers looked at the most common by counting the most common last names in phone books and selecting the most common names in each state. This hides significant diversity in names in large cities that may have had a greater mix of immigrant groups that the state overall; for instance, a map of the most common names just in New York City might look quite a bit different than the most common names in New York state.

Nonetheless, the concentration of last names serves as an echo of immigration and settlement patterns. British-origin names tend to dominate across the U.S., unsurprisingly, particularly Smith, Johnson, and Williams. Because slaves were often given the last names of their owners, a significant proportion of individuals with British last names are African American — for instance, African Americans are about 20% of people named Smith.

Several Irish-origin names stand out in Massachusetts, as well as some French surnames in Maine:

The map of Hawaii reflects the significance of the Asian population there:

Spanish-origin names in the Southwest:

The names common in the Great Lakes/upper plains region reflects the fact that the area was a common destination for immigrations from Germany and Scandinavia:

I looked up the geographers who created the maps (James Cheshire, Paul Longley, and Pablo Mateos at University College London) and that led me to an interesting website sponsored by UCL, the World Names Project. If you type in a surname, it will show where on the globe it is most common. You can also zoom in on individual nations and see the distribution within them. Here’s the global distribution of my last name, Sharp:

You also get some data about the name: its origin, the top 10 regions and individual cities for that name, and the most common first names that go with it (which, in all the names I tried, were overwhelmingly male, so I don’t know what to make of that).

As Sara said of the National Geographic map, many of the results are predictable, but that doesn’t mean it’s not fun to look at them.

UPDATE: Reader Kristina provides an explanation for why male names dominate the most common first names lists: