Washington State Route 509

State Route 509
Route information
Auxiliary route of I-5
Defined by RCW 47.17.680
Maintained by WSDOT
Length:	35.16 mi (56.58 km)
Existed:	1964 – present
Major junctions
South end:	I-705 in Tacoma
	SR 99 in Federal Way SR 516 in Des Moines SR 518 in Burien
North end:	SR 99 in Seattle
Highway system
State Highways in Washington Interstate • US • State Former PSH • 1964 renumbering • Former ← SR 508 SR 510 →

SR 509 cable stay bridge in Tacoma, Washington

State Route 509 is a state highway in the U.S. state of Washington. It extends just over 35 miles (56.6 km) from Tacoma in the south to Seattle in the north.

Route description

Originating at Interstate 705 in Tacoma, it travels over a cable-stayed bridge as a four-lane limited access highway east towards Fife before turning northward, skirting the Tacoma tideflats and rounding Brown's Point to Dash Point State Park. Entering King County it winds on top of the bluff along the south shore of Poverty Bay through Federal Way until connecting with State Route 99. It then follows SR 99 and State Route 516 into Des Moines and Normandy Park. It continues north as a four-lane freeway, skirting the western edge of the Seattle-Tacoma International Airport and intersecting State Route 518 in Burien. The route descends to the Duwamish River and terminates in the Industrial District south of downtown Seattle, where it rejoins State Route 99.

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	I-705 to SR 7 / I-5 / Schuster Parkway – Ruston, Seattle, 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	SR 99 south	South end of SR 99 overlap
		18.6	16th Avenue South – Saltwater State Park	Former SR 509 north
	Kent	21.58	SR 99 north / SR 516 east to I-5 – Seatac, Kent	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	SR 99 to I-5 / South 188th Street – Des Moines	Interchange
	Seatac
		South end of freeway
	Burien	29.82	South 160th Street
		30.40	SR 518 to I-405 / I-5 – Renton, Burien, Sea-Tac Airport
		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	Northbound exit is via Cloverdale Street
		34.39	Cloverdale Street – South Park	Northbound exit and southbound entrance
		35.17	SR 99 south (West Marginal Way) – South Park
		35.17	SR 99 north – Seattle	Continuation beyond SR 99 south

External links

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