About one in every 10 Americans report Irish ancestry, per U.S. Census data from 2020-2024.
The big picture: Descendants of Irish immigrants are most heavily concentrated in the northeast, and are least concentrated in the Southeast, per the data.
In Madison County, the share is 9%, in line with the national average of 9.4%.
Limestone County reports 11.1%, Morgan County 8.4% and Marshall County 7.3%.