O’Driscol, [38]
O’Driscols, various, [299]
O’Dwyer, Edmund, titular Bishop of Limerick, [159], [272], [274]
O’Dwyer, Colonel Edmund, [290]
O’Flaherty, Donogh, [299]
O’Flaherty clan, [5], [7], [8], [39]
Ogarney river, [115]
O’Grady, Captain Henry, [11]
O’Hagan, Shane, [168]
O’Hartegan, Matthew, Jesuit, [34], [35], [99], [100], [103], [121], [305]