The Kings of Moylurg were a branch of the Sil Muiredaig , and a kindred family to the Ua Conchobair Kings of Connacht. Their ancestor, Maelruanaidh Mor mac Tadg, was a brother to Conchobar mac Tadg, King of Connacht 967-973, ancestor of the O Connor family of Connacht. Maelruanaidh Mor mac Tadg is said to have made a deal of some nature where, in return for abandoing any claim to the provincial kingship, he would be given Moylurg. His dynasty were known as the Clan Mulrooney, and later still took the surname of MacDermot. The following is a list of their Kings, followed by the respective heads of the family up to the present day.

• Maelruanaidh Mor mac Tadg, fl. 956.
• Muirchertach mac Maelruanaidh Mor.
• Tadhg mac Muirchertach
• Maelruanaidh mac Tadhg, fl. 1080.
• Tadhg Mor mac Maelruanaidh, 1120-1124.
• Maelsechlainn mac Tadhg Mor, 1124.
• Dermot mac Tadhg Mor , 1124-1159; progenitor of the surname MacDermot .
• Muirgius mac Tadhg More , 1124-1159.
• Conchobair MacDermot , 1186-1197.
• Tomaltach na Cairge MacDermot , 1197-1207.
• Cathal Carrach MacDermot , 1207-1215.
• Dermot MacDermot , 1215-1218.
• Cormac MacDermot , 1218-1244
• Muirchertach MacDermot , 1245-1265
• Tadhg MacDermot , 1256-1281.
• Dermot Mideach MacDermot , 1281-1287
• Cathal MacDermot , 1288-1294
• Maelruanaidh MacDermot , 1294-1331.
• Tomaltach gCear MacDermot , 1331-1336.
• Conchobhair MacDermot , 1336-1343
• Ferghal MacDermot , 1343-1368.
• Aedh MacDermot , 1368-1393.
• Maelruanaidh MacDermot , 1393-1398.
• Conchobair Og MacDermot , 1398-1404.
• Ruaidri Caech MacDermot , 1404-1421.
• Tomaltach an Einigh MacDermot , 1421-1458.
• Aedh MacDermot , 1458-1465.
• Conochobar Og MacDermot , 1456-1478.
• Ruaidri Og MacDermot , 1478-1486.
• Conchobair MacDermott , 1486-1497.
• Tadhg MacDermot , 1497-1499.
• Cormac MacDermot , 1499-1528.
• Dermot an Einigh MacDermot , 1528-1533.
• Eoghan MacDermot , 1533-1534.
• Aedh na Ab MacDermott , 1534-1549.
• Ruaidri MacDermot , 1549-1568.
• Turlough MacDermot 1568-1576.
• Tadhg MacDermot , 1576-1585; last de facto King of Moylurg.
• Brian na Carriag MacDermot , 1585-1595. MacDermot of the Carrick
• Conchobar Og MacDermot 1595-1603, MacDermot of the Carrick.
• Brian Og MacDermot , 1603-1636, MacDermot of the Carrick.
• Turlough MacDermot , 1636-c.1652; styled Chief of the Name .
• Cathal Roe MacDermot , c.1652-c.1694, Chief of the Name.
• Hugh MacDermott , c.1694-1707, Chief of the Name.
• Charles MacDermott , 1707-1758, first to be styled Prince of Coolavin .
• Myles MacDermot , died 1758-1792, Prince of Coolavin.
• Hugh MacDermott , M.D., 1792-1824, Prince of Coolavin.
• Charles Joseph MacDermot , J.P. ,1824-1873, Prince of Coolavin.
• Hugh Hyacinth MacDermott ,1873-1904, Prince of Coolavin.
• Charles Edward MacDermott , 1904-1947, Prince of Coolavin.
• Dermot MacDermot , 1947-1989, Prince of Coolavin
• Niall Anthony MacDermot , 1989-2003, Prince of Coolavin.
• Rory MacDermot , 2004- The MacDermot , Prince of Coolavin, Chief of the Name.

References:

• "Mac Dermot of Moylurg: The Story of a Connacht Family", Dermot Mac Dermot, 1996.
• http://www.macdermot.com/