Tomás Óg de Burca
Tomás Óg de Búrca, 5th Mac William Íochtar (died 1460) was an Irish chieftain and noble who was lord of Lower (North) Connacht, Ireland. Tomás was the son of son of Thomas mac Edmond Albanach de Búrca, 2nd Mac William Íochtar (d.1402). He succeeded his brothers, Walter mac Thomas de Búrca, 3rd Mac William Íochtar (d.1440) and Edmund na Féasóige de Búrca, 4th Mac William Íochtar (d.1458) as chieftain in 1458. He was succeeded by his brother, Risdeárd de Búrca, 6th Mac William Íochtar (d.1473).