(Steirisches) Thermenland is in Styria. To the east of the Thermenland the Termenwelt is located in Burgenland. Both offer great spas.
The hot springs of Styria have a long tradition, and have become really popular. You can get everything a beauty spa could possibly offer.
Usually you will get to the region either from Graz or Vienna. Buses and Trains operate to all of the spas. However you may have to change your transportation vehicle a few times.
Lots of people just daytrip to a spa from Graz or Vienna.
If you plan to stay in one of the spas for more than a day, you may also consider to stay in one of the villages more to the center of the region and daytrip to various spas.