Dermod Ruadh O'Brien, 5th Baron of Inchiquin (October 1594 – 29 December 1624) was an Irish baron.
[1] Dermod, who was born in October 1594, was the son of Murrough O'Brien, 4th Baron Inchiquin (1562 – 24 July 1597), the son of Murrough McDermot O'Brien, 3rd Baron Inchiquin and Mabel Nugent, daughter of Christopher Nugent, 6th Baron Delvin.
[2] He inherited the barony at the age of two.
Dermod O'Brien married Ellen, eldest daughter of Sir Edmund FitzJohn FitzGerald of Cloyne and Ballymaloe House in County Cork,[2] from that powerful Hiberno-Norman family.
They had four sons,[3][a] and several daughters: