River Isar

Isar
The river Isar near Munich.
Country	Germany, Austria
Basin features
Main source	Eiskarlspitze, Alps, Austria. 1,160 m (3,810 ft) 47°22′29″N 11°24′43″E / 47.37472°N 11.41194°E / 47.37472; 11.41194
River mouth	Danube 48°48′11″N 12°58′35″E / 48.80306°N 12.97639°E / 48.80306; 12.97639Coordinates: 48°48′11″N 12°58′35″E / 48.80306°N 12.97639°E / 48.80306; 12.97639
Basin size	±9,000 km2 (3,500 sq mi)
Physical characteristics
Length	295 km (183 mi)
Discharge	Average rate: 175 m3/s (6,200 cu ft/s)

The Isar is a river in Tyrol, Austria and Bavaria, Germany. Its source is in the Karwendel range of the Alps in Tyrol; it enters Germany near Mittenwald, and flows through Bad Tölz, Munich, and Landshut before reaching the Danube near Deggendorf. At 295 km (183 mi) in length, it is the fourth largest river in Bavaria, after the Danube, Inn, and Main. It is Germany's second most important tributary of the Danube after the Inn.

One theory is that the name Isar comes from the hypothetical Indo-European root *es or *is, which meant "flowing water" and later turned into a word for frozen water (hence English ice, German: Eis) in Proto-Germanic. An older theory is that it comes from Celtic words and the name Isar is a construction of the Celtic stems ys "fast, torrential" and ura "water, river". According to another interpretation ys may mean "high" as well as "low", referring to the rapidly changing water level in the river Isar. In the ancient settlement area of the Celts several related river names can be found:

It may be possible that the ancient name of the lower part of the river Danube, Ister, has the same source. Newer interpretations relate it to the Proto-Basque particle *(w)its-, "water", also seen in similar but otherwise unexplained river names, such as Vézère, Vizela, Weser and Vistula.