Which river forms 187 km of the Germany-Poland border? The answer is the Oder.
The Oder rises in the Czech Republic and flows north through Poland before reaching the Szczecin Lagoon and, ultimately, the Baltic Sea. A 187-kilometre section forms part of the Germany-Poland frontier, making it one of Europe’s most historically significant boundary rivers.
The border is associated with the Oder-Neisse line, established after the Second World War. At the Potsdam Conference, the victorious Allies placed former German territories east of the Oder and Lusatian Neisse under Polish administration. East Germany recognised the frontier in 1950, while reunified Germany confirmed it in the 1990 German-Polish Border Treaty.
The Oder is also known as the Odra in Polish and Czech usage. It is easy to confuse it with the Vistula, Poland’s longest river, or the Warta, the Oder’s largest tributary. The river’s border section is only part of its course, which extends roughly 840 kilometres in total.