The Collaborative International Dictionary of English v.0.48:

Homesteader \Home"stead*er\, n.
   One who has entered upon a portion of the public land with
   the purpose of acquiring ownership of it under provisions of
   the homestead law, so called; one who has acquired a
   homestead in this manner. [Local, U.S.]
   [1913 Webster]

WordNet (r) 3.0 (2006):

homesteader
    n 1: someone who settles lawfully on government land with the
         intent to acquire title to it [syn: squatter,
         homesteader, nester]