Largest Scotch-Irish population, Illinois counties

Illinois counties ranked by the number of residents who are Scotch-Irish ancestry, from the 2024 American Community Survey detailed-origin tables. Each list covers the full eligible universe; download the complete data as CSV. This list covers the 100 counties in Illinois that qualify, ranked against each other statewide. The median across all 100 is 224. Biggest climber in the top 100 since 2020: Johnson County, IL, up 43 places to #52.