Orne
The Orne in Caen
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Location
Country	France
Physical characteristics
Source
• location	Aunou-sur-Orne
• elevation	240 m (790 ft)
Mouth
• location	English Channel
• coordinates	49°16′42″N 0°13′34″W / 49.27833°N 0.22611°W / 49.27833; -0.22611
Length	170 km (110 mi)
Basin size	2,932 km2 (1,132 sq mi)
Discharge
• average	27.5 m3/s (970 cu ft/s)

The Orne (French: [ɔʁn] ^ⓘ) is a river in Normandy, within northwestern France. It is 170 km (110 mi) long.^[1] It discharges into the English Channel at the port of Ouistreham. Its source is in Aunou-sur-Orne, east of Sées. Its main tributaries are the Odon and the Rouvre.

The Orne flows through the following departments and towns:

• Orne (named after the river): Sées, Argentan
• Calvados: Thury-Harcourt, Saint-André-sur-Orne, Caen, Ouistreham

It also flows through the area known as Suisse Normande.^[2]

Its longest tributaries are, from source to mouth:^[1]

• Don
• Ure
• Cance
• Udon
• Baize
• Rouvre
• Noireau
• Laize
• Odon

The name of the Orne in Normandy, which is referred to as the Olinas by Ptolemy,^[3] is a homonym of Fluvius Olne, the Orne saosnoise in Sarthe, which Xavier Delamarre traces back to the Celtic olīnā (elbow).

The waters of the Orne are typically moderately turbid and brown in colour. Its pH level has been measured at 8.5^[4] at the town of St. Andre sur Orne where summer water temperatures approximate 18 °C (64 °F). Electrical conductivity of the water has been measured at 30 microsiemens per centimeter.^{[citation needed]}

• Canal de Caen à la Mer
• Operation Tonga

• Media related to Orne River (Northwestern France) at Wikimedia Commons

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