Austria is a largely mountainous country due to its location in the Alps. The Central Eastern Alps, Northern Limestone Alps and Southern Limestone Alps are all partly in Austria. Of the total area of Austria (84 000 km² or 32,000 sq. mi), only about a quarter can be considered low lying, and only 32% of the country is below 500 metres (1,640 ft). The high mountainous Alps in the west of Austria flatten somewhat into low lands and plains in the east of the country.
Austria may be divided into 5 different areas. The biggest area are the Austrian Alps, which constitute 62% of Austria's total area. The Austrian foothills at the base of the Alps and the Carpathians account for around 12% of its area. The foothills in the east and areas surrounding the periphery of the Pannoni low country amount to about 12% of the total landmass. The second greater mountain area (much lower than the Alps) is situated in the north. Known as the Austrian granite plateau, it is located in the central area of the Bohemian Mass, and accounts for 10% of Austria. The Austrian portion of the Viennese basin comprises the remaining 4%.
Eastern Alps is the name given to the eastern half of the Alps, which where the the Austrian Alps were usually located. It usually defined as the area east of the Splügen Pass in eastern Switzerland. North of the Splügen Pass, the Posterior Rhine forms the border, and south of the pass, the Liro river and Lake Como form the boundary line.
The Eastern Alps include parts of Switzerland, most of Austria and of Liechtenstein, as well as parts of southern Germany, northern Italy and of Slovenia. The eastern border are the Wienerwald (Vienna Woods) and the Viennese basin which is the transition zone to the Carpathian mountains.
The Eastern Alps are traditionally divided according to the Alpenvereins-Einteilung (arrangement of the Alpine Club) into several dozen small regions, each assigned to the Northern Calcareous Alps, the Central Eastern Alps or the Southern Calcareous Alps. Fuller details are given on those pages of the regions they contain.
The highest mountain in the Eastern Alps is Piz Bernina (4052 m) in Switzerland, followed by the Ortler (3905 m) in Italy/South Tyrol and then Großglockner (3798 m) in Austria.
During the Würm glaciation, the Eastern Alps were drier than the Western Alps, with the contiguous ice shield ending in the region of the Niedere Tauern in Austria. This allowed many species to survive the ice age in the Eastern Alps where they could not survive elsewhere. For that reason, many species of plants are endemic to the Eastern Alps.