The maps on this page are based on the 1901 and 1911 census of Ireland, the data for which is available here: Census of Ireland. I generate maps based on the exact spelling used in the census. For example, McCann, M'Cann, Mc Cann, MacCann and Mac Cann all have there own set of maps. At the end of this page you will find a large list of surnames, which appear in either of the two census, that have a spelling similar to that of the surname Mac Cárthaigh. A huge amount of effort has gone into the production of these maps and I have been very careful to ensure that the census data has been processed as accurately as possible. However, I take no responsibility should I have failed in any way in this regard. Nor shall I be held responsible for any errors on the official census website. As stated, the census is available online enabling you to confirm the information presented here for yourself.
The numbers in brackets represent the number of people with the given surname in 1901. If the surname is followed by a zero then it only occured in the 1911 census.
Please feel free to comment or place an enquiry of interest to people with the Mac Cárthaigh surname.