Lower Austria (German: Niederösterreich) is the northeast state of the nine states or Bundesländer in Austria. The capital of Lower Austria since 1986 is Sankt Pölten (most recent capital town in Austria), but formerly, the capital of Lower Austria was Vienna, even though Vienna is not properly part of Lower Austria. With a land area of 19,174 km² and a population of 1.6 million people, it is the largest state in Austria, and in terms of population second only to Vienna (which also is a federal state).

Located east of Upper Austria, Lower Austria derives its name from where it is situated on the Danube River, which flows from west to east. The state borders on Slovakia, the Czech Republic, and on the other Austrian states of Upper Austria, Styria and Burgenland. The state surrounds Vienna.