The Salzkammergut is one of the most beautiful holiday regions in Austria. The name is coming from it's history. As the premier spot for Salt("Salz") Mining. As Salt is and was important it was directly controlled by the Emperors in Vienna - that's where the name "Kammer" came from.
The Salzkammergut is the Austrian "Lake District" - you can find 70+ Lakes (including very small mouintain ones) in an alpine surrounding
It is the greatest lake of Austria, who is only within the Austrian border. The Water is drinkable, like most of the lakes, and the temperature in summer between 20° and 22° Celsius.
The temperature is most of the time less than 20° Celsius.
Cities a little bit outside of the Salzkammergut but still part of it (According to their Marketing)
The TV series "Schlosshotel Orth" is playing there.