Schloss Hartheim

Schloss Hartheim, also known as Hartheim Castle, is a castle at Alkoven in Upper Austria, some 14 kilometres (9 mi) from Linz, Austria. It was built by Jakob von Aspen in 1600, and it is a prominent Renaissance castle in the country.

The building became notorious as one of the centers for the Nazi program known as Aktion T4, in which German citizens deemed mentally or physically unfit were systematically murdered with poison gas. After the official end of Aktion T4 in August 1941, the facility was used to murder Jews, communists, and other concentration camp prisoners under a program known as "Action 14f13".

In this capacity it was known as the Hartheim killing centre, where the Nazis murdered a total of 30,000 people.