The Illyrians and the Celts were followed by the Romans, who advanced until the Danube. To protect this natural border, the Romans built Carnuntum. Their rule came to an end with the age of tribal migrations.

Settlement by the Bavarians in the 6th century had been interrupted by the Avars and the Slavs. It was not until the victories of Charlemagne that the rule over the land was consolidated by the creation of the "Ostmark" (Eastern Province).

In 955, Otto the Great defeated the Magyars (Hungary) in the battle of Augsburg. In 976, his son Otto II confered the Ostmark on Leopold von Babenberg. After the last Babenberg ruler had died childless in 1246, the Holy Roman Empire´s newly elected king Rudolf of Habsburg won the Babenberg lands in 1278.

At the end of the 15th century, the Hungarians under Matthias Corvinus conquered almost all of Lower Austria until Emperor Maximilian restored the rule of the Habsburgs.

The Turks, who reached the gates of Vienna in 1529 and 1683, devastated the land two times.

The 18th century brought a time of economic and cultural ascendency, which lasted until the years 1805 and 1809, when the French Wars also affected Lower Austria.

After the collapse of the Danube monarchy in 1918, Lower Austria was declared a proper province of the Republic of Austria. In 1986, St. Pölten was elected the province capital of Lower Austria.