The Diocese of Lebus is a former diocese of the Catholic Church. It was erected in 1125 and suppressed in 1598. The Bishop of Lebus was also, ex officio, the ruler of a lordship that was coextensive with the territory of the diocese. The geographic remit included areas that are today part of the land of Brandenburg in Germany and the Province of Lubusz in Poland. It included areas on both sides of the Oder River around the town of Lebus. The cathedral was built on the castle hill in Lubusz and was dedicated to St Adalbert of Prague. Later, the seat moved to Górzyca, back to Lebus and finally to Fürstenwalde on the River Spree.

The Oder is a river in Central Europe. It is Poland's second-longest river in total length and third-longest within its borders after the Vistula and Warta. The Oder rises in the Czech Republic and flows 742 kilometres (461 mi) through western Poland, later forming 187 kilometres (116 mi) of the border between Poland and Germany as part of the Oder–Neisse line. The river ultimately flows into the Szczecin Lagoon north of Szczecin and then into three branches that empty into the Bay of Pomerania of the Baltic Sea.