The Collaborative International Dictionary of English v.0.48:

Northerner \North"ern*er\, n.
   1. One born or living in the north.
      [1913 Webster]

   2. A native or inhabitant of the Northern States; --
      contradistinguished from Southerner. [U. S.]
      [1913 Webster]

WordNet (r) 3.0 (2006):

Northerner
    n 1: an inhabitant of the North
    2: an American who lives in the North (especially during the
       American Civil War) [syn: Yankee, Yank, Northerner]