The Spree is, with a length of approximately 400 kilometres (250 mi), the main tributary of the River Havel. The Spree is much longer than the Havel, which it flows into at Berlin-Spandau; the Havel then flows into the Elbe at Havelberg. The river rises in the Lusatian Highlands, that are part of the Sudetes, in the Lusatian part of Saxony, where it has three sources: the historical one called Spreeborn in the village of Spreedorf, the water-richest one in Neugersdorf, and the highest elevated one in Eibau. The Spree then flows northwards through Upper and Lower Lusatia, where it crosses the border between Saxony and Brandenburg. After passing through Cottbus, it forms the Spree Forest, a large inland delta and biosphere reserve. It then flows through Lake Schwielochsee before entering Berlin, as Müggelspree (pronounced [ˈmʏɡl̩ˌʃpʁeː] ).

The Havel is a river in northeastern Germany, flowing through the states of Mecklenburg-Vorpommern, Brandenburg, Berlin and Saxony-Anhalt. The 325 kilometres (202 mi) long Havel is a right tributary of the Elbe. However, the direct distance from its source to its mouth is only 94 kilometres (58 mi). For much of its length, the Havel is navigable; it provides an important link in the waterway connections between the east and west of Germany, as well as beyond.