France Ill: River in Alsace, France

It flows through the plain of Alsace. It is an important left tributary of the Rhine river. It is the main river of Alsace. It flows through the Haut-Rhin and the Bas-Rhin departments in the Grand Est region.

Ill
The Ill in the Petite France quarter of Strasbourg. The river's only lock can be seen right of centre.
Location
Country	France
Region	Grand Est
Physical characteristics
Source
- location	Jura mountains
- elevation	570 m (1,870 ft)
Mouth
- location	Rhine
- coordinates	48°42′1″N 7°55′52″E / 48.70028°N 7.93111°E / 48.70028; 7.93111
Length	217 km (135 mi)
Basin size	4,760 km2 (1,840 sq mi)
Basin features
Progression	Rhine→ North Sea
Tributaries
- left	Aar, Bruche, Doller, Souffel, Thur

The Ill river is 216.7 kilometres (134.7 miles) long. Its drainage basin has an area of 4,760 square kilometres (1,838 square miles).

Course

The Ill starts in the northern side of the Glaserberg mountain, in the Jura Mountains near the Swiss border, in the commune of Winkel, (Haut-Rhin department), at an altitude of about 560 metres (1,837 feet). From here, the Ill flows first to the east to Ferrette and to Illfurth where it is joined by the Largue river, the main right tributary of the Ill.

From Illfurth, the Ill runs northward through Alsace, flowing parallel to the Rhine river.

The Ill river flows within the Grand Est region, 2 departments and 70 communes. It flows through the following communes, among others:

• Haut-Rhin : Illfurth, Frœningen, Hochstatt, Zillisheim, Brunstatt-Didenheim, Mulhouse, Bourtzwiller, Illzach, Sausheim, Ruelisheim, Ensisheim, réguisheim, Meyenheim, Oberentzen, Niederentzen, Biltzheim, Oberhergheim, Niederhergheim, Sainte-Croix-en-Plaine, Logelheim, Sundhoffen, Andolsheim, Horbourg-Wihr, Colmar, Illhaeusern
• Bas-Rhin : Sélestat, Ebersmunster, Kogenheim, Sermersheim, Huttenheim, Benfeld, Matzenheim, Osthouse, Erstein, Nordhouse, Hipsheim, Eschau, Illkirch-Graffenstaden, Ostwald, Strasbourg, Offendorf

Five communes in the Alsace have their names from the riverː

• Bas-Rhin
  • Illkirch ("the church of the Ill")
• Haut-Rhin
  • Illfurth ("a place to cross the Ill")
  • Illtal ("the valley of the Ill")
  • Illhaeusern ("the village of the Ill")
  • Illzach

Finally, the Ill river flows into the Rhine river in the commune of Offendorf, just to the north of Strasbourg.

The main tributaries of the Ill river are all left tributaries; the right tributaries are very short streams. Only the Largue starts in the Jura Mountains; the rest have their sources in the Vosgues mountains, to the east.

• Largue - 50.5 kilometres (31.4 miles)
• Doller - 46.5 kilometres (28.9 miles)
• Thur - 53.3 kilometres (33.1 miles)
• Lauch - 50 kilometres (31 miles)
• Fecht - 49 kilometres (30 miles)
• Giessen - 33.6 kilometres (20.9 miles)
• Andlau - 42 kilometres (26 miles)
• Ehn - 36.5 kilometres (22.7 miles)
• Bruche - 76.7 kilometres (47.7 miles)

Its average yearly discharge (volume of water which passes through a section of the river per unit of time) is 59.70 cubic metres per second (2,108 cubic feet per second) at Strasbourg in the Bas-Rhin department, for the period 1974 - 2017.

Average monthly discharge (m³/s) at Strasbourg (1974 - 2017)

•  
  Source of the Ill in Winkel.
•  
  The Ill in Sélestat.
•  
  The Ill and the St Paul's church in Strasbourg.
•  
  The Ill in Strasbourg.

• List of rivers of France