The Limestone Alps (German: Kalkalpen) are the two mountain ranges, roughly 600 kilometres (370 mi) long, which run parallel to the main mountain range of the Austrian Central Alps and to its north and south. They are known as the (Northern and Southern Limestone Alps respectively.
The best-known mountain groups in the Limestone Alps are:
- in the north the Rätikon, Wetterstein, Wilder Kaiser, Steinberge, Dachstein massif, Totes Gebirge, Gesäuse, Hochschwab and the local Vienna mountains, the Rax and the Schneeberg
- in the south, the Dolomites, Carnic Alps and Karavanken.
The mountain and hill profiles of the Limestone Alps are very varied and range from jagged peaks and rock faces to high plateaus and extensive areas of karst. They are of economic importance, not least because they are sources of drinking water and have many accessible dripstone and ice caves.
Whilst the central Alps are mainly composed of crystalline rock (granite, gneiss) or slate (the High Tauern), the Limestone Alps are made of lighter and more porous rock. In addition to limestone, they contain dolomite, marl, sandstone and the like.