Territorial evolution of Germany

The territorial evolution of Germany in this article includes all changes in the modern territory of Germany from its unification making it a country on 1 January 1871 to the present, although the history of both "Germany" as a territorial polity concept and the history of the ethnic Germans are much longer and much more complex. Modern Germany was formed when the Kingdom of Prussia unified most of the German states, with the exception of multi-ethnic Austria (which was ruled by the German-speaking royal family of Habsburg and had significant German-speaking land), into the German Empire. As a result of its loss in the First World War, the 1919 Treaty of Versailles stipulated that Germany cede about 13% of its territory to its neighbours; its colonies were lost at the same time. The Weimar Republic was formed two days before the end of fighting in WWI. This republic included territories to the east of today's German borders.

The period of Nazi rule from the early 1930s through the end of the Second World War brought significant territorial losses for the country. Nazi Germany initially expanded the country's territory dramatically and conquered most of Europe, though not all areas were added to Germany officially. However, the Nazi plan for the near future was the establishment of a Greater Germanic Reich including most of Europe. The Nazi regime eventually collapsed, and the four Allies occupied Germany.

Nazi annexations from the time of its annexation of Austria on 13 March 1938 were annulled while the former eastern territories of Germany before Nazi annexation of Austria were ceded to Poland and the Soviet Union and the Oder and Neisse Rivers became Germany's new eastern boundary. This territory became Poland's so-called "Recovered Territories", while approximately one-third of East Prussia became the Russian Federation's Kaliningrad Oblast. In the west, the Saar area (Saarland) formed one French-controlled protectorate with its own high autonomy.

The western part of Germany was unified as the Trizone, becoming the Federal Republic of Germany on 23 May 1949 ("West Germany"). Western-occupied West Berlin declared its accession to the Federal Republic of Germany in 1949 but was denied by the occupying powers. The Soviet zone of Germany in the east, including the Soviet sector of Berlin, became the communist German Democratic Republic ("East Germany") on 7 October of the same year. On 1 January 1957, the Saar Protectorate (which was separated from Germany on 17 December 1947) became a part the Federal Republic of Germany, as provided by its Grundgesetz (constitution) article no. 23 ("Little reunification"). East Germany, including East Berlin, became parts the Federal Republic of Germany on 3 October 1990 – an event referred to as German reunification.