• Agnew
• Alexander
• Mac Allister from Scotland
• Mac Ardle (page 669)
• Arthur (page 477)
• Bird, see Mac Neny
• Boylan (Vol. II, page 577)
• O Brassil (page 608)
• Mac Brock (page 670)
• Brody (page 383)
• Mac Cabe, chiefs of Monaghan, and Cavan
• O Callaghan of Oriel
• Cairns (page 374) and (page 672)
• Mac Campbell of Tyrone (page 509)
• Mac Cann, lords of Clanbrassil (page 584)
• Carbery of Orgiall (page 377)
• O Carroll, princes of Oriel or Louth (page 672)
• Casey (page 453)
• Cassidy, chiefs of Coole
• Mac Clean from Scotland
• Colcan (pages 608)
• Colgan of Ulster (page 671)
• Coleman of Orgiall (page 383)
• Connolly, chiefs in Fermanagh (Vol. II, page 577)
• O Connor of Orgiall (page 639)
• Cooley (page 453)
• Corrigan (page 390)
• Corry (page 572)
• Cosgrave (see Mac Oscar)
• Mac Court (page 539)
• Culkins (see Colcan)
• Mac Cusker (see Mac Oscar)
• Mac Daniel (see Mac Donald)
• Davin, Davine (see Devin, Devine)
• Devers (page 671)
• Devin, lords of Fermanagh, Devine (page 403)
• Divers (page 671)
• Mac Donald, of Wicklow, and San Francisco (page 525)
• Donegan
• Donelan (page 419)
• Mac Donnell, of Antrim (from Scotland) (page 527)
• Mac Donnell, of Leinster (page 534)
• Mac Donnell, Mac Daniel of Clankelly, in Fermanagh (page 536)
• Donnelly (page 420)
• Mac Dougald, Mac Dougall, Mac Dowell (from Scotland) (page 539)
• O Duffy (page 670)
• O Dwyer (page 513)
• Eagan, Mac Egan
• Mac Elligott, Elliott, from Scotland (Vol. II, page 578)
• Enright, Hanratty (page 670)
• Mac Evoy (pages 565-566; Mac Evoy, Mac Veagh, and Mac Veigh are the anglicised forms of the ancient Mac Uais who were distinguished chieftains in the territory now known as the barony of "Moygoish," in the county Westmeath.)
• Feehan (page 446 and 513)
• O'Flanagan of Clan Colla (page 654)
• Flinn (page 452)
• Fogarty, of Ulster (page 669)
• Garvey of Orgiall (page 466)
• Gavan (page 420 and 467)
• Gilchreest
• Mac Gilfinan, lords of Pettigoe (page 818)
• Mac Gilmichael (page 818)
• Mac Gilmore, chiefs in Down and Antrim (page 820)
• Goff, Mac Gough, Mac Geough
• Mac Grath, chiefs in Fermanagh (page 575)
• Griffin (page 670)
• Mac Hale (page 536)
• O Hanlon, lords of Orior, in Armagh, and Royal standard bearers of Ulster (page 663)
• O Hanratty, Enright (page 670)
• O Hart, princes of Tara, lords of Teffia, and chiefs in Sligo (page 664)
• Healy
• Heany (pages 818, 672)
• Higgins (page 669)
• Hodges (page 383)
• Hopkins (page 383)
• Hort (see O'Hart)
• Howard (of England)
• Mac Hugh (page 542)
• Mac Ivir, Mac Ivor
• Kearns (see Cairns)
• Keenan, chiefs in Fermanagh
• O Kelly of Ulster (page 671)
• Mac Kenna, chiefs of Truagh in Monaghan (page 543)
• Kennedy (page 670)
• Kern (see Cairns)
• Keogh
• Kieran (see Cairns)
• Kiernan (page 509)
• Kinitty (see Kennedy)
• Lally
• Lane of Ulster (page 513)
• Lannin
• Larkin (page 513 and 514)
• Laury (page 670)
• Lavan (page 514)
• Lawlor, Lalor (page 514)
• O Loghan, O Loghnan
• Loftus
• Looney
• Lynch (page 669)
• Magee, chiefs in Down and Antrim (page 542)
• Magrath
• Maguire, princes and lords of Fermanagh, and barons of Enniskillen (page 576)
• Mac Mahon, princes of Monaghan, lords of Farney, and barons of Dartry, at Conagh, where they held their chief seat; the MacMahons were sometimes styled Princes of Orgiall, and several of them changed their names to "Matthews" (page 549)
• Malone of Ulster (pages 513, 579)
• Mac Manus, chiefs in Fermanagh (page 553)
• Matthews, see Mac Mahon
• Meldon (see Muldoon)
• Mitchell (page 639)
• Monaghan (page 639)
• Mooney (page 593)
• Muldoon (anglicised "Meldon"), chiefs of Lurg
• Mullally
• Mulrooney (page 818 and 672)
• Muregan
• Nawn, see Mac Neny
• Nealan, Neillan (page 604)
• Mac Neny, O Neny (page 670)
• Mac Oscar and Mac Osgar (anglicised Mac Cusker and Cosgraye), who, according, to O'Dugan, possessed a territory called Fearra Hois (signifying the "Men of Ross"), which comprised the district of Magheross about the town of Carrickmacross, in the county Monaghan, with the parish of Clonkeen, adjoining, in the county Louth
• Ouseley
• Pigeon (page 382)
• Mac Quillian, powerful chiefs in Antrim (from Scotland) (Vol. II, page 578)
• Roberts (see Mac Evoy)
• Roderick (page 383)
• Rogan (page 671)
• Rogers (see Mac Rory)
• Ronan, Ronayne
• Mac Rory (anglicised "Rogers")
• Saunders, Saunderson
• Shannon (page 640)
• Mac Sheehy (page 558)
• Slevine
• Mac Tague (anglicized Montague)
• Mac Ternan (see Mac Tiernan)
• Mac Tiernan (page 565)
• Mac Tully
• Mac Uais (page 565)
• Vaughan (see Feehan)
• Mac Veagh and Mac Veigh (page 565)
• Wesley