It is known for Ossiach Abbey, founded about 1000. The monastery church was first mentioned in a 1028 deed, hence the first of the Order of Saint Benedict in the Duchy of Carinthia. Restored in a Late Gothic style after a fire in 1484, the nowadays parish church has Baroque decoration with stucco of the Wessobrunner School. At the northern side of the building is the tomb of King Bolesław II the Bold of Poland († 1081). Two stained glass windows were donated by Karl May in 1905, though the author had never visited Ossiach. Today the church is also renowned for the Carinthischer Sommer classical music festival, held around July and August each year. The pianist Wilhelm Backhaus held his last concert here on June 29, 1969.
A chapel of ease stands in the village of Tauern. First mentioned in 1290, the Tauernkirche was rebuilt in 1519 in a Late Gothic style and received a Baroque equipment including a high altar in the 17th century.