In 1659, Sir William Petty compiled a list of persons with title to land in Ireland. Sometimes called "Pender's Census," it was published in 1939 (Irish Manuscripts Commission, A Census of Ireland, circa 1659, with Supplementary Material from the Poll Money Ordinances 1660-1611, Seamus Pender, ed., Dublin: Stationary Office, 1939). Petty also recorded the total numbers of Irish and English inhabitants in each townland and the pricipal Irish names in each barony. In order to be considered a principal name, there had to be a minimum of ten families with the name residing within the barony.
The surname Desmond appears in only one barony. It is listed as principal surname in the barony of Kinalea in County Cork as "MacDesmond" Thus, according to Petty's survey there were at least ten families with the surname MacDesmond residing in the barony of Kinalea in 1659. We have no way of knowing how many Desmonds or "MacDesmonds" might have been residing in the other baronies of County Cork. This is not much information, but it is enough to tell us that the center of distribution of families with the surname in 1659 was in Kinalea. From 1659 to about 1845 when Griffith's Valuation was compiled, the surname, while still numerous in the area of Kinalea and Kinsale, seems to have spread northwest to the area between Kinalea and Macroom and north to Cork City.
The maps showing the distribution of the surname for the 1766 Religious Census and the Tithe Applotment Books (1823-1837) do not accurately portray the distribution of the surname. The 1766 Religious Census contains information for less than a third of the parishes in County Cork, and the Tithe Applotment Books contain information only for families living on agricutural tracts of an acre or more.
A Map Showing the Center of Distribution of Families with the Surname
MacDesmond in the Barony of Kinalea, County Cork, Ireland, 1659