The Oder River
Oder River, (Czech and Polish: Odra,), a river in central Europe, about 540 miles (870 km) long. From its source in Moravia, Czech Republic, it flows northeastward into Poland, where it turns to the northwest, forming part of the boundary between Germany and Poland. The Neisse and Warta are the chief tributaries. The Oder empties into the Oder Lagoon, an inlet of the Baltic Sea, and is navigable upstream to Racibórz, Poland. Tributaries and canals connect it with the Elbe and Vistula rivers, and with Berlin on the Spree.
Major cities on the Oder include Ostrava, Czech Republic; Wroclaw, Poland; Frankfurt, Germany; and Szczecin, Poland.