Two possible etymologies for Whitaker or Whittaker:
(Locality). The north part of a graveyard allotted to the poor was called whittaker, from wite, a penalty, and acre,--a place of burial for criminals. A culprit who could not discharge the penalty or wite became a 'witetheow,' and was buried in the wite-acre. Bailey defines Whittaker 'the north-east part of a flat or shoal--the middle ground.'
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.
English: habitational name from any of various places named with Old English hwit ‘white’ or hw?te ‘wheat’ + æcer ‘cultivated land’, as for example Whitaker in Lancashire and Whitacre in Warwickshire (both ‘white field’) or Whiteacre in Kent and Wheatacre in Norfolk (both ‘wheat field’).
Source: Dictionary of American Family Names, Oxford University Press, ISBN 0-19-508137-4