Depends what kind of lot you're looking for. There are lots of horse properties up that way, anywhere from 1-5+ acres. Some can be subdivided, some cannot. Developers (DR Horton, Toll Brothers, etc) have a hold on some of the larger tracts of land, but there are undeveloped plots available up this way also.
I live in the area and am happy to help with your search. Drop me a note via Trulia if you'd like more information. There's land out there to build upon, for sure.