German ancestry is #1, English ancestry is #2

[𝕭𝖆𝖕𝖙𝖎𝖘𝖙𝖆 𝕸𝖎𝖓𝖔𝖑𝖆]

German American-ness is pretty interesting because it is still widely reported and recognized as an ancestry but it stopped being a distinct sociopolitical identity a long time ago. It could be argued that German American culture not only assimilated into generic middle American culture but effectively came to dominate it, especially in food (after barbecue, what image does "real American food" conjure in the rest of the world if not hamburgers, hot dogs and lager beers with names like Budweiser?).

[𝕭𝖆𝖕𝖙𝖎𝖘𝖙𝖆 𝕸𝖎𝖓𝖔𝖑𝖆]

Most common last names by state:

https://blogs.ancestry.com/cm/whats-the-most-popular-surname-in-your-state/

Interestingly no German surnames show up in the top three in any state, not even in Wisconsin.  Besides the obvious Spanish dominance in California, Texas and the Southwest, and Asians in Hawaii - you see a few ethnic identifiers (Sullivan in Massachusetts, Olson in North Dakota, more Johnsons and Andersons in the Upper Midwest).

It is very interesting that Jones is in the top three in Kentucky and Tennessee (and Maryland and Virginia but no other state). As Al has mentioned, the only remaining trace of older Welsh settlement in Appalachia.