Maguire (also spelled "Mac Guire" or "McGuire") is an Irishsurname from the GaelicMac Uidhir, which is "son of Odhar" or "son of the brown-haired one". According to legend, the eleventh in descent from Colla da Chrich, great-grandson of Cormac mac Airt, monarch of Ireland about the middle of the third century.