Duwamish River

Duwamish River
The lower Duwamish Waterway and the First Avenue South Bridge (State Route 99), looking north. Slips 1, 2, and 3 can be seen on the eastern bank. Kellogg Island is the crescent-shaped island in the upper right portion. Terminal 115 is located in the central portion
Country	United States
State	Washington
Cities	Seattle, Tukwila
Source	Green River
Mouth	Elliott Bay
Length	12 mi (19 km)
Map of the Duwamish/Green River watershed with the Duwamish highlighted

The Duwamish River is the name of the lower 12 miles (19 km) of Washington state's Green River. Its industrialized estuary is known as the Duwamish Waterway.

The native Lushootseed name of the Duwamish River (and of the Cedar River) was Dx^wdəw. The Lushootseed name of the Duwamish tribe was Dx^w'Dəw?Abš or Dkh^w'Duw'Absh, meaning 'People of the Inside'. Both of these have been anglicized as Duwamish.

Until 1906, the White and Green Rivers combined at Auburn, and joined the Black River at Tukwila to form the Duwamish. In 1906, however, the White River changed course following a major flood and emptied into the Puyallup River as it does today. The lower portion of the historic White River—from the historic confluence of the White and Green Rivers to the conjunction with the Black River—is now considered part of the Green River. Later, in 1911 the Cedar River was diverted to empty into Lake Washington instead of into the Black River; at that time, the lake itself still emptied into the Black River. Then, with the opening of the Lake Washington Ship Canal in 1916, the lake's level dropped nearly nine feet and the Black River dried up. From that time forward, the point of the name change from Green to Duwamish is no longer the confluence of the Green and Black Rivers, though it has not changed location.

The Duwamish Waterway empties into Elliott Bay in Seattle. After the completion of the man-made Harbor Island in 1909, the mouth of the river was divided into two channels, the East and West Waterways.