Washington State Route 900

State Route 900
Map of King County in western Washington with SR 900 highlighted in red
Route information
Auxiliary route of I-90
Maintained by WSDOT
Length	16.20 mi[1] (26.07 km)
Existed	1964[2]–present
Major junctions
West end	I-5 in Tukwila
Major intersections	SR 167 in Renton I-405 / SR 169 in Renton
East end	I-90 in Issaquah
Location
Country	United States
State	Washington
County	King
Highway system
State highways in Washington Interstate US State Scenic Pre-1964 1964 renumbering Former
← SR 823 → SR 902

State Route 900 (SR 900) is a state highway serving part of King County, Washington, United States. It travels 16 miles (26 km) between southern Seattle and the Eastside suburbs of Renton and Issaquah, separated by the Issaquah Alps. The highway terminates to the west at an interchange with Interstate 5 (I-5) in Tukwila and to the east at I-90 in Issaquah, and also has intermediate junctions with I-405 and SR 167 in Renton.

SR 900 was created in the 1964 state highway renumbering, but the corridor had been part of the state highway system since 1909. It was originally a section of the Sunset Highway, the main cross-state route between Seattle and Spokane and was designated as U.S. Route 10 (US 10) in 1926. After the opening of the Lake Washington Floating Bridge, US 10 was moved to a new highway and the former alignment through Renton became an alternate route and a branch of Primary State Highway 2 that was replaced by SR 900. The highway originally terminated at an interchange with I-90 in Seattle's Rainier Valley, but was truncated in 1991.