city, capital of Opolskie województwo (province), southwestern Poland, situated on the Oder River. Opole began as the home of the Slavic Opolanie tribe; the earliest mention of it was in the 9th century. In 1202 it became the capital of the Opole principality, which included the entire Upper Silesia region. The town passed to Bohemia (1327), the Habsburgs (16th century), and Prussia (1742) and was returned to Poland in 1945.

Opole is an important river port and rail link between Wrocław and Upper Silesia; its economy depends on cement industries and iron foundries. A regional museum, a university, theatres, and many notable historic buildings are located there. An annual festival of Polish songs is a popular cultural event. Pop. (2002) 129,946.