State Route 509 is a state highway in the U.S. state

U.S. state

A U.S. state is any one of the 50 federated states of the United States of America that share sovereignty with the federal government. Because of this shared sovereignty, an American is a citizen both of the federal entity and of his or her state of domicile. Four states use the official title of...

 of Washington. It extends just over 35 miles (56.6 km) from Tacoma

Tacoma, Washington

Tacoma is a mid-sized urban port city and the county seat of Pierce County, Washington, United States. The city is on Washington's Puget Sound, southwest of Seattle, northeast of the state capital, Olympia, and northwest of Mount Rainier National Park. The population was 198,397, according to...

 in the south to Seattle

Seattle, Washington

Seattle is the county seat of King County, Washington. With 608,660 residents as of the 2010 Census, Seattle is the largest city in the Northwestern United States. The Seattle metropolitan area of about 3.4 million inhabitants is the 15th largest metropolitan area in the country...

 in the north.

Route description

Originating at Interstate 705 in Tacoma, it travels over a cable-stayed bridge

Cable-stayed bridge

A cable-stayed bridge is a bridge that consists of one or more columns , with cables supporting the bridge deck....

 as a four-lane limited access highway east towards Fife

Fife, Washington

Fife is a city in Pierce County, Washington, United States. The population was 9,173 at the 2010 census.-History:In 1940, it was described as "Fife...at a valley crossroads in the midst of a thickly settled berry growing and truck-gardening district is represented by a string of markets, taverns,...

 before turning northward, skirting the Tacoma tideflats and rounding Brown's Point to Dash Point State Park

Dash Point State Park

Dash Point State Park in King and Pierce Counties, Washington, is one of the Washington State Parks. It consists of including of saltwater shoreline on Puget Sound. Available activities include camping, beachcombing, hiking, biking, fishing, swimming, birdwatching, windsurfing, Skimboarding and...

. Entering King County

King County, Washington

King County is a county located in the U.S. state of Washington. The population in the 2010 census was 1,931,249. King is the most populous county in Washington, and the 14th most populous in the United States....

 it winds on top of the bluff along the south shore of Poverty Bay through Federal Way

Federal Way, Washington

Federal Way is a city in King County, Washington, United States. Federal Way is located between Seattle and Tacoma. Its western boundary is Puget Sound. It is bordered by Des Moines on the north, Kent, unincorporated King County, and Milton on the east and Tacoma and Fife on the south...

 until connecting with State Route 99

State Route 99 (Washington)

State Route 99, abbreviated SR 99, commonly called Highway 99, is a numbered state highway in the U.S. state of Washington extending just under from Fife in the south to Everett in the north, with a gap in Tukwila.-Southern division:...

. It then follows SR 99 and State Route 516 into Des Moines

Des Moines, Washington

Des Moines is a city in King County, Washington, United States. The population was 29,673 at the 2010 census. Property within the city has been the subject of land buyouts because of noise from aircraft landing or taking off from the Seattle-Tacoma International Airport two miles to the north of...

 and Normandy Park

Normandy Park, Washington

Normandy Park is a city in King County, Washington, United States. The population was 6,335 at the 2010 census.Based on per capita income, Normandy Park ranks 26th of 522 areas in the state of Washington.-History:...

. It continues north as a four-lane freeway, skirting the western edge of the Seattle-Tacoma International Airport

Seattle-Tacoma International Airport

The Seattle–Tacoma International Airport , also known as Sea–Tac Airport or Sea–Tac , is an American airport located in SeaTac, Washington, at the intersections of State Routes 99 and 509 and 518, about west of Interstate 5...

 and intersecting State Route 518

State Route 518 (Washington)

State Route 518 is a state highway in the U.S. state of Washington. It extends just under 3.5 miles from Burien in the west to Tukwila in the east.-Route description:...

 in Burien

Burien, Washington

Burien is a city in King County, Washington, United States, located south of Seattle. As of the 2010 Census, Burien's population is 33,313, which is a 2.9% increase since incorporation. Annexation in 2011 has increased the cities population to about 45,000....

. The route descends to the Duwamish River

Green River (Washington)

The Green River is a long river in the state of Washington in the United States, arising on the western slopes of the Cascade Mountains south of I-90....

 and terminates in the Industrial District

Industrial District, Seattle, Washington

The Industrial District is the principal industrial area of Seattle, Washington. It is bounded on the west by the Duwamish Waterway and Elliott Bay, beyond which lies Delridge of West Seattle; on the east by Interstate 5, beyond which lies Beacon Hill; on the north by S King and S Dearborn Streets,...

 south of downtown Seattle, where it rejoins State Route 99

State Route 99 (Washington)

State Route 99, abbreviated SR 99, commonly called Highway 99, is a numbered state highway in the U.S. state of Washington extending just under from Fife in the south to Everett in the north, with a gap in Tukwila.-Southern division:...

.

Proposed extension

A proposal to link SR 509 directly to I-5 south of Sea-Tac Airport is expected to relieve congestion by attracting much truck traffic to the more direct route. The project will also include adding extra lanes to the section of I-5 that is south of the SR 509 interchange to accommodate additional traffic.

Major intersections

County	Location	Mile	Destinations	Notes
Pierce	Tacoma	0.00	Tacoma City Center	Continuation beyond I-705
		0.00	, Portland	Interchange
		South end of freeway
		0.79	Portland Avenue	Northbound exit and southbound entrance
		2.35	Port of Tacoma Road
		North end of freeway
		6.39	11th Street	Former SR 509 south
King	Federal Way	17.48		South end of SR 99 overlap
		18.6	16th Avenue South – Saltwater State Park Saltwater State Park Saltwater State Park is a plot of second-growth timber on Puget Sound in the City of Des Moines, Washington, United States halfway between Seattle and Tacoma. The main attraction is of saltwater beachfront, including a sandy swimming beach in the southwest corner, and rocky tideflats along the...	Former SR 509 north
	Kent	21.58		North end of SR 99 overlap; south end of SR 516 overlap
	Des Moines
		23.37	Marine View Drive	North end of SR 516 overlap; former SR 509 south
	Burien	28.09		Interchange
	Seatac
		South end of freeway
	Burien	29.82	South 160th Street
		30.40	, Sea-Tac Airport Seattle-Tacoma International Airport The Seattle–Tacoma International Airport , also known as Sea–Tac Airport or Sea–Tac , is an American airport located in SeaTac, Washington, at the intersections of State Routes 99 and 509 and 518, about west of Interstate 5...
		31.66	South 128th Street
		32.65	5th Avenue South, Glendale Way South	Southbound exit and northbound entrance
	Seattle	34.39	Myers Way – White Center White Center, Washington White Center is a census-designated place in King County, Washington, United States. It lies between Seattle and Burien part of which was annexed by Burien on 1 April 2010. The population was 13,495 at the 2010 census.-Geography:...	Northbound exit is via Cloverdale Street
		34.39	Cloverdale Street – South Park South Park, Seattle, Washington South Park is a neighborhood in the city of Seattle, in the U.S. state of Washington. It is located just south of Georgetown across the Duwamish River, and just north of the city of Tukwila. Its main thoroughfares are West Marginal Way S. , S. Cloverdale Street and 14th Ave. S...	Northbound exit and southbound entrance
		35.17	– South Park South Park, Seattle, Washington South Park is a neighborhood in the city of Seattle, in the U.S. state of Washington. It is located just south of Georgetown across the Duwamish River, and just north of the city of Tukwila. Its main thoroughfares are West Marginal Way S. , S. Cloverdale Street and 14th Ave. S...
		35.17		Continuation beyond SR 99 south

External links

• Highways of Washington State
• Project page for the proposed SR 509 expansions