Pirna is a town in the Free State of Saxony, Germany, capital of the administrative district Sächsische Schweiz-Osterzgebirge. The town's population is over 37,000. Pirna is located near Dresden and is an important district town as well as a Große Kreisstadt. It is also known for the gassing of about 15,000 disabled people in Sonnenstein Castle between June 1940 and August 1941, killings which ceased after pressure was exerted on the authorities by the local population.