Situated within the Nock Mountains range of the Gurktal Alps, about 20 kilometres (12 miles) north of the city of Villach, Arriach houses the geographical centre of the state of Carinthia.

The municipal area consists of the four cadastral communities: Arriach proper, Innerteuchen, Laastadt, and Sauerwald.

In early modern times, the remote area was a centre of Crypto-protestantism in the Duchy of Carinthia.

It is located at the site of a former 'prayer house' (Bethaus), built after the Patent of Toleration was issued by the Habsburg emperor Joseph II in 1781.

Arriach also features several historic rustic log homes preserved in quite good condition.