The Lenne is a tributary of the river Ruhr in the Sauerland hills, western Germany. It has caused flooding in recent years.^[2]

Lenne
The Lenne in Iserlohn-Letmathe.
Location
Country	Germany
Physical characteristics
Source
• location	Sauerland
• elevation	819 m (2,687 ft)
Mouth
• location	Ruhr
• coordinates	51°24′54″N 7°29′31″E / 51.41500°N 7.49194°E / 51.41500; 7.49194
Length	129.0 km (80.2 mi) [1]
Basin size	1,355 km2 (523 sq mi) [1]
Discharge
• average	25 m3/s (880 cu ft/s)
Basin features
Progression	Ruhr→ Rhine→ North Sea
Tributaries
• left	Else (Lenne), Bigge (river), Elspe (Lenne), Grafschaft (Lenne), Uentrop (Lenne)
• right	Nesselbach (Lenne), Nette (Lenne), Sorpe (Lenne)

Having its source on top of the Kahler Asten near Winterberg in an intermittent spring at an elevation of 2,687 ft (819 m), the Lenne ends after a course of 129 km flowing into the Ruhr river near the city of Hagen. With an average discharge of 25 m³/s near its mouth, it is the main tributary of the Ruhr. ^{[citation needed]}