Lower Austria (German: Niederösterreich [ˈniːdɐˌʔøːstɐʁaɪç] (listen); Czech: Dolní Rakousy; Slovak: Dolné Rakúsko) is the northeasternmost of the nine states of Austria. Since 1986, the capital of Lower Austria has been St. Polten, the most recently designated capital in Austria. Previously, Lower Austria's capital was Vienna, even though Vienna has not officially been part of Lower Austria since 1921. With a land area of 19,186 km2 (7,408 sq mi) and a population of 1.612 million people, Lower Austria is the country's largest state; it is the second most populous after the federal state of Vienna. Other main cities are Amstetten, Krems an der Donau and Wiener Neustadt.
Situated east of Upper Austria, Lower Austria derives its name from its downriver location on the Enns River, which flows from west to east. Lower Austria has an international border, 414 km (257 mi) long, with the Czech Republic (South Moravia Region) and Slovakia (Bratislava and Trnava Regions). The state has the second longest external border of all Austrian states. It also borders the other Austrian states of Upper Austria, Styria and Burgenland as well as surrounding Vienna.
Lower Austria is divided into four regions, known as Viertel (quarters):
- Weinviertel or Tertiary Lowland (below the Manhartsberg)
- Waldviertel or Bohemian Plateau (above the Manhartsberg)
- Mostviertel (above the Vienna Woods)
- Industrieviertel (below the Vienna Woods).
These regions have different geographical structures. Whilst the Mostviertel is dominated by the foothills of the Limestone Alps with mountains up to 2,000 m (AA) high, most of the Waldviertel is a granite plateau. The hilly Weinviertel lies to the northeast, descends to the plains of Marchfeld in the east of the state, and is separated by the Danube from the Vienna Basin to the south, which in turn is separated from the Vienna Woods by a line of thermal springs (the Thermenlinie) running north to south.
- Schneeberg (Klosterwappen; 2,076 m)
- Rax (Scheibwaldhöhe; 1,943 m; highest summit: Heukuppe; 2,007 m – Styria)
- Ötscher (1,893 m)
- Dürrenstein (1,878 m)
- Schneealpe (Ameisbühel; 1,828 m; highest summit: Windberg; 1,903 m – Styria)
- Hochkar (1,808 m)
- Gamsstein (1,774 m)
- Stumpfmauer (1,770 m)
- Göller (1,766 m)
- Hochwechsel (1,743 m)
- Gippel (1,669 m)
- Großer Sonnleitstein (1,639 m)
- Großer Zellerhut (1,639 m)
- Gemeindealpe (1,626 m)
- Scheiblingstein (1,622 m) (not to be confused with Scheiblingstein (2,197 m), which is in Styria)
- Drahtekogel (1,565 m)
- Sonnwendstein (1,523 m)
- Obersberg (1,467 m)
- Königsberg (1,452 m)
- Großer Sulzberg (1,400 m)
- Reisalpe (1,399 m)
- Gahns (1,380 m)
- Tirolerkogel (1,377 m)
- Türnitzer Höger (1,372 m)
- Unterberg (1,342 m)
- Traisenberg (1,230 m)
- Dürre Wand (1,222 m)
- Hohenstein (1,195 m)
- Eisenstein (1,185 m)
- Hohe Wand (1,132 m)
- Großer Peilstein (1,061 m)
- Weinsberg (1,041 m)
- Hocheck (1,036 m)
- Nebelstein (1,017 m)
- Eibl (1,007 m)
- Hohe Mandling (967 m)
- Jauerling (961 m)
- Anninger (675 m)
- Buschberg (491 m)
Other mountains in Lower Austria may be found at Category:Mountains of Lower Austria.
The state border with Styria runs over both passes.
The most important rivers north of the Danube (on its left bank) are the Ysper, Kamp, Krems, Lainsitz, March and Thaya. South of the Danube (on its right bank) are the Enns, Ybbs, Erlauf, Melk, Pielach, Traisen, Schwechat, Fischa, Schwarza, Triesting, Pitten and the Leitha.
- Ottenstein Reservoir (4.3 km2)
- Lunzer See (0.69 km2)
- Erlaufsee (0.56 km2, of which about half lies in Lower Austria)
- Erlauf Reservoir
- Wienerwaldsee (0.32 km2)
Lower Austria is rich in natural caves; in all 4,082 have been recorded. Most of the caves have formed in limestone and dolomite rocks and are therefore called karst caves. Cavities also form in the marble of the Central Alps and the Bohemian Massif. Among the largest caves in Lower Austria are:
- Ötscherhöhlensystem (Ötscher): 27,003 m long; union of the Taubenloch and Geldloch
- Pfannloch (Ötscher): 5,287 m long
- Lechnerweidhöhle (Dürrenstein): 5,252 m long
- Trockenes Loch (Schwarzenbach an der Pielach): 4,510 m long
- Hermannshöhle (Kirchberg am Wechsel): 4,430 m long
- Eisensteinhöhle (Bad Fischau): 2,341 m long
The history of Lower Austria is very similar to the history of Austria. Many castles are located in Lower Austria. Klosterneuburg Abbey, located here, is one of the oldest abbeys in Austria. Before World War II, Lower Austria had the largest number of Jews in Austria.
Lower Austria is divided into four regions: Waldviertel, Mostviertel, Industrieviertel, and Weinviertel. The Wachau valley, situated between Melk and Krems in the Mostviertel region, is famous for its landscape, culture, and wine.