Isar

The Isar is a river in Tyrol, Austria and Bavaria, Germany, which is not navigable for watercraft above raft size. 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 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 generally meant "flowing water" and later turned into a word with a meaning narrowed to frozen water 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:

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