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Verlaufskarte Inn DE.png
Map highlighting the Inn River
CountriesSwitzerland, Austria, Germany
Physical characteristics
 ⁃ locationSwiss Alps (Lägh dal Lunghin)
 ⁃ elevation2,484 m (8,150 ft)
 ⁃ location
Danube (Passau)
 ⁃ coordinates
 ⁃ elevation
291 m (955 ft)
Length518.5 km (322.2 mi) [1]
Basin size26,053 km2 (10,059 sq mi) [1]
 ⁃ average740 m3/s (26,000 cu ft/s)
Basin features
ProgressionDanubeBlack Sea



The name Inn is derived from the old Celtic words en and enios, meaning water. In a document of 1338, the river was named Wasser (German for water). The first written mention from the years 105 to 109 (Publii Corneli Taciti historiarium liber tertius) reads: "... Sextilius Felix... ad occupandam ripam Aeni fluminis, quod Raetos Noricosque interfluit, missus..." ("... Sextilius Felix was sent to capture the banks of the Inn, which flows between the Rhaetian people and the Noric people.")[3] The river is also mentioned by other authors of the Roman Empire as Ainos (Greek) or Aenus (Latin). In medieval Latin it was written as Enus or Oenus. The change in the old Bavarian language from e to i turned Enus to In. Until the 17th century, it was written like this or Yn, but also Ihn or Yhn. The double-n appeared only in the 16th century, for example in the Tyrolian Landreim of 1557, and since the 18th century this spelling and pronunciation with a short vowel has been customary.[4]

The mentions in Roman times refer to the lower course. The Tyrolean section was first called Aenus by Venantius Fortunatus in the 6th century. The name Engadin and the Romansh name En indicate that the upper reaches of the river have always been called this way.[citation needed] Even though it was occasionally believed that the Inn originated near the Adige at the Reschen Pass, since the 16th century at the latest the origin has been seen uniformly in the area of the lakes at the Maloja Pass.[4]





In Passau the Inn finally enters the Danube (as does the river Ilz there). Although the Inn has a greater average flow than the Danube when they converge in Passau, and its watershed contains the Piz Bernina, the highest point in the Danube watershed, the Inn is considered a tributary of the Danube, which has a greater length, drains a larger surface area, and has a more consistent flow. The Inn is the only river originating in Switzerland that ends in the Black Sea (via the Danube).


View of the Upper Inn Valley. On the right is the entrance to the Ziller Valley.


Years 1921/2006[6]


2013 floodEdit

The Old City of Passau during the flood
Water level marks on the Town Hall in Passau


Hydroelectric power plantsEdit

Currently, there are 24 hydroelectric power plants on the Inn. 17 of them are operated by Verbund AG.[8] The power plants are listed beginning at the headwaters:

Islas[9] 4.3 17
Ova Spin[10] 50 100
Pradella[11] 288 1,000
Martina[12] 70 290
Imst[13] 89 550
Kirchbichl[14] 19.3 131
Langkampfen[15] 31.5 169
Oberaudorf-Ebbs 60 268
Nussdorf 48 245.8
Rosenheim 35 179.5
Feldkirchen 38 204
Wasserburg 29 165.7
Teufelsbruck 25 150.4
Gars 30 169.2
Jettenbach 6 30.2
Töging 85 564.6
Neuötting 26 159.4
Perach 19 128.4
Stammham 23 136.4
Braunau-Simbach 100 550
Ering-Frauenstein 72 434
Egglfing-Obernberg 84 485
Schärding-Neuhaus 96 541.8
Passau-Ingling 86 504.7


  12. ^ Cite error: The named reference en3 was invoked but never defined (see the help page).

External linksEdit