The Inn (; ; ) is a

river A river is a natural stream of fresh water that flows on land or inside Subterranean river, caves towards another body of water at a lower elevation, such as an ocean, lake, or another river. A river may run dry before reaching the end of ...

Switzerland Switzerland, officially the Swiss Confederation, is a landlocked country located in west-central Europe. It is bordered by Italy to the south, France to the west, Germany to the north, and Austria and Liechtenstein to the east. Switzerland ...

Austria Austria, formally the Republic of Austria, is a landlocked country in Central Europe, lying in the Eastern Alps. It is a federation of nine Federal states of Austria, states, of which the capital Vienna is the List of largest cities in Aust ...

and

Germany Germany, officially the Federal Republic of Germany, is a country in Central Europe. It lies between the Baltic Sea and the North Sea to the north and the Alps to the south. Its sixteen States of Germany, constituent states have a total popu ...

. The long river is a right

tributary A tributary, or an ''affluent'', is a stream or river that flows into a larger stream (''main stem'' or ''"parent"''), river, or a lake. A tributary does not flow directly into a sea or ocean. Tributaries, and the main stem river into which they ...

of the

Danube The Danube ( ; see also #Names and etymology, other names) is the List of rivers of Europe#Longest rivers, second-longest river in Europe, after the Volga in Russia. It flows through Central and Southeastern Europe, from the Black Forest sou ...

, being the third largest tributary of the Danube by discharge. The highest point of its

drainage basin A drainage basin is an area of land in which all flowing surface water converges to a single point, such as a river mouth, or flows into another body of water, such as a lake or ocean. A basin is separated from adjacent basins by a perimeter, ...

is the summit of

Piz Bernina Piz Bernina (Romansh language, Romansh, , ) is the highest mountain in the Eastern Alps, the highest point of the Bernina Range, and the highest peak in the Rhaetian Alps. It rises and is located south of Pontresina in the Bernina Region and ne ...

at . The

Engadin The Engadin or Engadine (;This is the name in the two Romansh idioms that are spoken in the Engadin, Vallader and Puter, as well as in Sursilvan and Rumantsch Grischun. In Surmiran, the name is ''Nagiadegna'', and in Sutsilvan, it is ''Gidegna'' ...

e, the valley of the En, is the only Swiss valley whose waters end up in the

Black Sea The Black Sea is a marginal sea, marginal Mediterranean sea (oceanography), mediterranean sea lying between Europe and Asia, east of the Balkans, south of the East European Plain, west of the Caucasus, and north of Anatolia. It is bound ...

(via the Danube).

Etymology

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.") 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.Otto Stolz: ''Geschichtskunde der Gewässer Tirols.'' Schlern-Schriften, Band 32, Innsbruck 1932, S. 6–14 und 83–88
Digitalisat
The mentions in Roman times refer to the lower course. The Tyrolean section was first called Aenus by

Venantius Fortunatus Venantius Honorius Clementianus Fortunatus ( 530 600/609 AD; ), known as Saint Venantius Fortunatus (, ), was a Latin poet and hymnographer in the Merovingian Court, and a bishop of the Early Church who has been venerated since the Middle Ages. ...

in the 6th century. The name

and the Romansh name ''En'' indicate that the upper reaches of the river have always been called this way. Even though it was occasionally believed that the Inn originated near the

Adige The Adige is the second-longest river in Italy, after the Po. It rises near the Reschen Pass in the Vinschgau in the province of South Tyrol, near the Italian border with Austria and Switzerland, and flows through most of northeastern Italy ...

at the

Reschen Pass Reschen Pass (, ; ) is a mountain pass across the main chain of the Alps, connecting the Upper Inn Valley in the northwest with the Vinschgau region in the southeast. Since 1919, the border between South Tyrol, Italy and Tyrol, Austria has app ...

, since the 16th century at the latest the origin has been seen uniformly in the area of the lakes at the

Maloja Pass Maloja Pass ( Italian: ''Passo del Maloja'', German: ''Malojapass'') (1815m a.s.l.) is a high mountain pass in the Swiss Alps in the canton of Graubünden, linking the Engadine with the Val Bregaglia, still in Switzerland and Chiavenna in ...

. A connection may exist between the name Inn and the name of the French river Ain.Arnaud Vendryes: ''L'Ain : le nom d'une rivière à travers les sources.'' In: Société d'Emulation du Jura, Travaux 2015, S. 147–168

Geography

The source of the Inn is located in the

Swiss Alps The Alps, Alpine region of Switzerland, conventionally referred to as the Swiss Alps, represents a major natural feature of the country and is, along with the Swiss Plateau and the Swiss portion of the Jura Mountains, one of its three main Physica ...

, west of St. Moritz in the

e region, which is named after the river ( Romansh ''Engiadina'';

Latin Latin ( or ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally spoken by the Latins (Italic tribe), Latins in Latium (now known as Lazio), the lower Tiber area aroun ...

''vallis Eniatina''). Shortly after it leaves its source, the Inn flows through the largest lakes on its course, Lake Sils and Lake Silvaplana. It runs north-eastwards, entering Austria, and from Landeck eastwards through the Austrian state of

Tyrol Tyrol ( ; historically the Tyrole; ; ) is a historical region in the Alps of Northern Italy and western Austria. The area was historically the core of the County of Tyrol, part of the Holy Roman Empire, Austrian Empire and Austria-Hungary, f ...

and its capital,

Innsbruck Innsbruck (; ) is the capital of Tyrol (federal state), Tyrol and the List of cities and towns in Austria, fifth-largest city in Austria. On the Inn (river), River Inn, at its junction with the Wipptal, Wipp Valley, which provides access to the ...

(''bridge over the Inn''), and crosses the border into

Bavaria Bavaria, officially the Free State of Bavaria, is a States of Germany, state in the southeast of Germany. With an area of , it is the list of German states by area, largest German state by land area, comprising approximately 1/5 of the total l ...

near Kufstein. On Bavarian territory the river runs northwards and passes Rosenheim, Wasserburg am Inn, and Waldkraiburg; then it turns east, runs through Mühldorf and

Neuötting Neuötting (, , in contrast to "Altötting, Old Ötting"; ) is a Town#Germany, town in the Altötting (district), district of Altötting, in Bavaria, Germany. It is situated on the river Inn (river), Inn, 2 km north of Altötting, about 70&nb ...

and is enlarged by two major tributaries, the Alz and the

Salzach The Salzach (Austrian: �saltsax ) is a river in Austria and Germany. It is in length and is a right tributary of the Inn (river), Inn, which eventually joins the Danube. Its drainage basin of comprises large parts of the Northern Limeston ...

. From here to the

, it forms the border between Germany (Bavaria) and Austria (

Upper Austria Upper Austria ( ; ; ) is one of the nine States of Austria, states of Austria. Its capital is Linz. Upper Austria borders Germany and the Czech Republic, as well as the other Austrian states of Lower Austria, Styria, and Salzburg (state), Salzbur ...

). Towns on this last section of the river are Marktl am Inn, Simbach on Inn, Braunau am Inn and Schärding. In

Passau Passau (; ) is a city in Lower Bavaria, Germany. It is also known as the ("City of Three Rivers"), as the river Danube is joined by the Inn (river), Inn from the south and the Ilz from the north. Passau's population is about 50,000, of whom ...

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).

Tributaries

* Right tributaries (in downstream order):

Flaz The Flaz is a river in the Swiss region of Engadin. It is a right tributary of the Inn. The Flaz starts at the confluence of Bernina with Roseg; after that Flaz flows in the territory of Pontresina and Samedan Samedan (, locally ) is a town ...

, Spöl, Clemgia, Faggenbach, Pitzbach, Ötztaler Ache, Melach, Sill, Ziller, Alpbach, Wildschönauer Ache, Brixentaler Ache, Weißache, Kaiserbach, Rohrdorfer Ache, Sims, Murn, Alz,

, Enknach, Mattig, Ach, Hartbach, Antiesen, Pram * Left tributaries (in downstream order; two different rivers called Rott exist): Beverin, Schergenbach, Sanna, Gurglbach, Höttinger Bach, Mühlauer Bach, Brandenberger Ache, Kieferbach, Auerbach, Kirchbach, Mangfall, Rott, Attel, Isen, Rott

Flow

The average discharge at the

mouth A mouth also referred to as the oral is the body orifice through which many animals ingest food and animal communication#Auditory, vocalize. The body cavity immediately behind the mouth opening, known as the oral cavity (or in Latin), is also t ...

of the Inn is .

2013 flood

On 3 June 2013 the discharge of the Inn in

reached and the water levels reached , the highest recorded historic flood level since 1501. The historic centre of Passau, where the

, Inn and Ilz converge, was flooded severely.

Hydroelectric power plants

Currently, there are 24

hydroelectric Hydroelectricity, or hydroelectric power, is Electricity generation, electricity generated from hydropower (water power). Hydropower supplies 15% of the world's electricity, almost 4,210 TWh in 2023, which is more than all other Renewable energ ...

power plants on the Inn. 17 of them are operated by Verbund AG. The power plants are listed beginning at the headwaters:

References

External links

* {{Authority control Rivers of Switzerland Rivers of Bavaria International rivers of Europe Engadin Celerina/Schlarigna La Punt Chamues-ch Madulain S-chanf Scuol Sils im Engadin/Segl Silvaplana St. Moritz Valsot Zernez Zuoz Rivers of Tyrol (federal state) Austria–Germany border Rivers of Graubünden Braided rivers in Europe Rivers of Austria Rivers of Germany