Oker

Oker
Confluence of the Oker and Aller near Müden
Location
Country	Germany
Physical characteristics
Source
• location	Harz Mountains
• coordinates	51°46′42″N 10°29′29″E / 51.77833°N 10.49139°E / 51.77833; 10.49139
• elevation	900 metres (3,000 ft)
Mouth
• location	Aller
• coordinates	52°31′26″N 10°21′39″E / 52.52389°N 10.36083°E / 52.52389; 10.36083
Length	128.2 km (79.7 mi)[1]
Basin size	1,822 km2 (703 sq mi)[1]
Basin features
Progression	Aller→ Weser→ North Sea

The Oker (pronounced [ˈoːkɐ]) is a river in Lower Saxony, Germany, that has historically formed an important political boundary. It is a left tributary of the River Aller, 128 kilometres (80 mi) in length and runs in a generally northerly direction.