Burgenland lies in the south of Austria and has four sub-regions: Neusiedlersee, Neusiedlersee-Hugelland, Mittelburgenland and Sudburgenland. Sudburgenland is the smallest of the subregions with 498 hectares. It is all the way in the south separated from Mittelburgenland by a small mountain, Geschriebenstein. Sudburgenland is most well-known for Blaufrankisch, and only Blaufrankisch can carry the DAC of Eisenberg. Eisenberg is a small village and also a vineyard site that is considered the best site in the region with its steep-sloping, blue slate soil.
For more information, check out this interesting, in-depth article from Stuart Pigott here.