Distribution of the Surnames in Ireland

The Irish times has graphics showing the distribution of the Variants of the Ui McCarthain  in mid 19th century Ireland primarily recorded in Griffiths Valuation:-

http://www.irishtimes.com/ancestor/surname/index.cfm?fuseaction=Go.&Surname=Carton&UserID=

An extract:-

Variants and total numbers.

Click to see county numbers.