“It was common for Scots-Irish extended families and even large segments of clans to settle in the same region. In Catawba County, North Carolina, over 300 Alexander families were identified in the first census of the United States in 1790.”
–– From “Southern Culture: An Introduction” by John Beck, Wendy Jean Frandsen and Aaron Randall (2009)
Update puzzler: I notice belatedly that Catawba County wasn’t created from Lincoln County until 1842.
One possible explanation: Mecklenburg County not only dates to 1762, but also included Hezekiah and numerous other Alexanders among its early residents. Even today among U.S. cities Charlotte is second only to Brooklyn (!) in Alexanders per capita.
Indeed, a quick search on HeritageQuest shows that Mecklenburg had more Alexander heads of household in 1790 than any other North Carolina county. However, the number was 55 (out of 118 statewide), far from over 300. As a matter of fact, the number of Alexanders enumerated in Mecklenburg doesn’t seem to go over 300 until 1910 (I’m setting aside a truly aberrant result of 902 that pops up in 1880. It is so clearly out of line with the numbers for decades before or after that it doesn’t seem reasonable to take it at face value).