Family History and Genealogy Resources by Surname
McNamara Surname Origin
(Origin Celtic) From Mac, son, and cu-marra or or con-marra, 'the hero of the sea.' Con-marra was descended from Cas, King of Thomond, from whom came McConmara, or Macnamara. This family were anciently hereditary lords in the County of Clare.
Source: An Etymological Dictionary of Family and Christian Names With an Essay on their Derivation and Import; Arthur, William, M.A.; New York, NY: Sheldon, Blake, Bleeker & CO., 1857.
McNamara Surname Meaning and Family Facts
There is more to McNamara family history than the origin of your surname:
A McNamara Family History Thought:
'Those who forget their past are destined to repeat it.' --Robert A. Heinlein