Source : Webster's Revised Unabridged Dictionary (1913)

Northwestern \North`west"ern\, a.
   Of, pertaining to, or being in, the northwest; in a direction
   toward the northwest; coming from the northwest;
   northwesterly; as, a northwestern course.

Source : WordNet®

northwestern
     adj 1: situated in or oriented toward the northwest [syn: {northwesterly},
             {northwest}]
     2: of a region of the United States generally including
        Washington; Oregon; Idaho; and sometimes Montana; Wyoming