|• location||Ankershagen, Mecklenburg|
|• elevation||65 m (213 ft)|
|22 m (72 ft)|
|Length||325 km (202 miles)|
|Basin size||23,858 km2 (9,212 sq mi)|
|• average||103 m3/s (3,600 cu ft/s)|
|• minimum||18.8 m3/s (660 cu ft/s)|
|• maximum||215 m3/s (7,600 cu ft/s)|
|Progression||Elbe→ North Sea|
|• left||Woblitz, Briese, Tegeler Fließ, Spree, Nuthe, Plane, Buckau|
|• right||Rhin, Dosse|
The Havel (German: [ˈhaːfl̩] (listen)) is a river in northeastern Germany, flowing through the states of Mecklenburg-Vorpommern, Brandenburg, Berlin and Saxony-Anhalt. It is a right tributary of the Elbe and 325 kilometres (202 mi) long. 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.
The source of the Havel is located in the Mecklenburg Lake District, between Lake Müritz and the city of Neubrandenburg. There is no obvious visible source in the form of a spring, but the river originates in the lakes in the Diekenbruch near Ankershagen, close to and south-east of the watershed between the North and Baltic seas. From there the river initially flows southward, eventually joining the Elbe, which in turn flows into the North Sea. Every river north-east of it flows to the Baltic Sea. The river enters Brandenburg near the town of Fürstenberg. In its upper course and between Berlin and Brandenburg an der Havel the river forms several lakes.
The Havel's main tributary is the Spree, which joins the Havel in Spandau, a western borough of Berlin, and is longer and delivers more water than the Havel itself above the confluence. The second largest tributary is the Rhin, named in the Middle Ages by settlers from the lower Rhine. At the southern end of the Ruppiner See, weirs can distribute the waters of the Rhin either east- or westwards, rejoining the Havel in two places 67 kilometres (42 mi) apart along a straight line, and more than 160 kilometres (99 mi) apart along the course of the river.
The region around and north of the middle Havel is called the Havelland. It consists of sandy hills, often called Ländchen, and low marshes, called luchs. A few kilometres of the river before its confluence with the Elbe near Havelberg are in the State of Saxony-Anhalt. Due to its minimal gradient it is susceptible to high waters in the Elbe.
Unless in extreme floods, if the dike of the Elbe is submerged, the discharge of the Havel is improved by the Gnevsdorfer Vorfluter (something like "Gnevsdorfer outfall"). By this canal, the mouth of the Havel, that naturally would be near Havelberg, is placed 11 km downstream. As the course of the Elbe has a higher gradient than the Havel, the water level of the Havel in Havelberg can be kept 1.4 metres below the Elbe (at the junction of the traverse communicating canal, protected by a lock).
Towns along the river include: Fürstenberg, Zehdenick, Oranienburg, Berlin, Potsdam, Werder, Ketzin, Brandenburg, Premnitz, Rathenow and Havelberg.
In earlier Greek or Latin sources, such as Tacitus's Germania, the name of the river was also written as Habola, Habula, Havela. The river name Havel is related to German Haff, habe, hafen, MHG Hafen meaning port, harbor).
The Slavic people who later moved into the Havel area were referred to in German sources as Heveller (occasionally as Havolane).