State Route 181 (SR 181, named the Valley Highway) is a

state highway A state highway, state road, or state route (and the equivalent provincial highway, provincial road, or provincial route) is usually a road that is either ''numbered'' or ''maintained'' by a sub-national state or province. A road numbered by a ...

serving

King County King County is located in the U.S. state of Washington. The population was 2,269,675 in the 2020 census, making it the most populous county in Washington, and the 13th-most populous in the United States. The county seat is Seattle, also the st ...

in the

U.S. state In the United States, a state is a constituent political entity, of which there are 50. Bound together in a political union, each state holds governmental jurisdiction over a separate and defined geographic territory where it shares its sover ...

Washington Washington commonly refers to: * Washington (state), United States * Washington, D.C., the capital of the United States ** A metonym for the federal government of the United States ** Washington metropolitan area, the metropolitan area centered o ...

. The highway, travelling north parallel to the

Green River Green River may refer to: Rivers Canada * Green River (British Columbia), a tributary of the Lillooet River *Green River, a tributary of the Saint John River, also known by its French name of Rivière Verte *Green River (Ontario), a tributary of ...

, begins at SR 516 in

Kent Kent is a county in South East England and one of the home counties. It borders Greater London to the north-west, Surrey to the west and East Sussex to the south-west, and Essex to the north across the estuary of the River Thames; it faces ...

and ends at an interchange with Interstate 405 (I-405) in Tukwila. The highway primarily serves as an alternate route to the SR 167 freeway, which travels east parallel to SR 181. The original route, between

Auburn Auburn may refer to: Places Australia * Auburn, New South Wales * City of Auburn, the local government area *Electoral district of Auburn *Auburn, Queensland, a locality in the Western Downs Region *Auburn, South Australia *Auburn, Tasmania *Aub ...

and Rainier Valley in

Seattle Seattle ( ) is a seaport city on the West Coast of the United States. It is the seat of King County, Washington. With a 2020 population of 737,015, it is the largest city in both the state of Washington and the Pacific Northwest regio ...

, was originally established in 1931 as a branch of Primary State Highway 1 (PSH 1) and in 1937 as Secondary State Highway 5M (SSH 5M). SSH 5M was renumbered to SSH 2M in 1959 and became SR 181 after the 1964 highway renumbering. SR 181 was shortened twice in the 1970s from Seattle to Tukwila and once more in 1991 from Auburn to Kent to form its present route, no longer connected to parent route SR 18.

Route description

SR 181 begins as the Valley Highway at an intersection with SR 516 west of Downtown

and an interchange between SR 516 and SR 167. The highway travels north and parallels the

and a pedestrian and bicycle trail to the west and the Interurban Trail to the east into Tukwila. SR 181 begins to parallel a

BNSF BNSF Railway is one of the largest freight railroads in North America. One of seven North American Class I railroads, BNSF has 35,000 employees, of track in 28 states, and nearly 8,000 locomotives. It has three transcontinental routes that ...

and

Union Pacific The Union Pacific Railroad , legally Union Pacific Railroad Company and often called simply Union Pacific, is a freight-hauling railroad that operates 8,300 locomotives over routes in 23 U.S. states west of Chicago and New Orleans. Union Paci ...

rail line to the east as it serves

Tukwila Station Tukwila station is a train station in Tukwila, Washington, United States. The station was built by Sound Transit to serve its Sounder commuter rail service on the S Line, as well as Amtrak's intercity ''Cascades'' line. It includes 390 ...

. The highway ends at a

partial cloverleaf interchange A partial cloverleaf interchange or parclo is a modification of a cloverleaf interchange. The design has been well received, and has since become one of the most popular freeway-to-arterial interchange designs in North America. It has also bee ...

with I-405, crossing over the Green River shortly before its northern terminus.

History

The West Valley Highway was built in the early 1910s, after an alignment on the west side of the White (now Green) River Valley was chosen by county engineers in 1909. SR 181 was formed during the 1964 state highway renumbering as a highway following the

Green Green is the color between cyan and yellow on the visible spectrum. It is evoked by light which has a dominant wavelength of roughly 495570 Nanometre, nm. In subtractive color systems, used in painting and color printing, it is created by ...

and

Duwamish Duwamish may refer to: * Duwamish tribe, a Native American tribe in Washington state * Duwamish River, in Washington state * ''Duwamish'' (fireboat) See also * Elliott Bay Elliott Bay is a part of the Central Basin region of Puget Sound. It is ...

rivers from SR 18 in

through

and Tukwila to SR 900 in

. The route was originally signed in 1937 as SSH 5M from PSH 5 in Auburn to U.S. Route 99 (US 99) and PSH 1, and in 1931 as a branch of PSH 1 from SSH 5M to PSH 2. SSH 5M was renumbered to SSH 2M in 1959 and the southern terminus of the highway was moved to a new branch of PSH 2. SSH 2M and the PSH 1 branch were combined into SR 181 in 1964, and was truncated to newly created SR 599 in 1971. The northern terminus was moved to its current location, an interchange with I-405 in 1979, and the southern terminus was moved to Kent in 1991. No major revisions to the route of the highway have occurred since 1991 and the highway is no longer connected to parent route SR 18.

Major intersections

References

External links

Highways of Washington State
{{Authority control 181 Transportation in King County, Washington