[2][3][4] Clandonagh barony is named after the Ó Donnchadha (Dunphy) clan who ruled the area during the Middle Ages.

The Erkina River flows through it, and the Slieve Bloom Mountains are in its north.

[11] Clan Moroghoe migrated from Clandonagh to their seat in County Cork in 1709.

[12] It is referred to in the topographical poem Tuilleadh feasa ar Éirinn óigh (Giolla na Naomh Ó hUidhrín, d. 1420): O'Cearḃaill dar corcraḋ croinn, O'Donnchaḋa dreaċ dioghoinn, Sloiġ liag as don tár toraid, Dá riġ iad a haonchonair.

("O'Cearbhaill for whom trees are ruddy, O'Donnchadha of honest aspect, Whose rocklike hosts possess the fruitful land, Are two kings of the same territory.