List of Interstate Highways in Washington


Markers for I-82 and I-182

Map of Washington's highways with the Interstates in red
System information
Notes: Maintained by the Washington State Department of Transportation (WSDOT)
Highway names
Interstates: Interstate X (I-X)
US Routes: U.S. Route X (US X)
State: State Route X (SR x)
System links
State highways in Washington
Interstate • US • State
Former PSH • 1964 renumbering • Former SR

Three primary, and four auxiliary routes make up the Washington state segment of the Interstate Highway System, totaling 764.27 miles (1,229.97 km).[n 1] These highways connect every city in the state with a population of over 100,000:[1] Seattle, Spokane, Tacoma, Vancouver, Bellevue, and Everett, as well as the state capital, Olympia.

Interstate 90 (I-90) is the longest primary Interstate Highway in Washington measuring 297.52 mi (478.81 km), while I-82 is the shortest at 132.57 mi (213.35 km). The longest auxiliary Interstate Highway in Washington is I-405 at 30.30 mi (48.76 km), and the shortest is I-705 at 1.50 mi (2.41 km). One route, I-605, has been proposed over the years to form another bypass around I-5 and I-405, however there are no plans to construct this fifth auxiliary route.

Contents

Primary Interstate Highways

Route Length Description Southern / western terminus Northern / eastern terminus References
I-5 276.62 miles (445.18 km) I-5 enters the state from Oregon, traveling north past the interchange with I-205 and through rural southwestern Washington. The highway passes the state capital Olympia, and turns northeast through Tacoma and I-705, before turning back north. I-405 is intersected, which serves the Eastside, as I-5 enters Seattle. After exiting Seattle, I-5 intersects I-405 again and heads towards Everett and meets the Canada – United States border in Blaine. I-5 at the Oregon state line BC 99 at the Canada – United States border [2][3][4][5]
I-82 132.57 miles (213.35 km) I-82 begins at an intersection with I-90 outside of Ellensburg, heading southeasterly by the Yakima Training Center and the city of Yakima, paralleling the Yakima River. I-82's sole auxiliary route, I-182, serves the Tri-Cities as I-82 and continues south into Oregon. I-90 in Ellensburg I-82 at the Oregon state line [3][6][7][8]
I-90 297.52 miles (478.81 km) I-90 begins just west of an interchange with I-5 in Seattle, heading east over floating bridges to Mercer Island and Bellevue, before traveling through more rural Western Washington, crossing the Cascade Mountains over Snoqualmie Pass before dropping into Eastern Washington at Ellensburg. I-82 is intersected outside of Ellensburg as the highway continues east through rural Eastern Washington before turning northeasterly and intersecting Spokane before leaving the state into Idaho. SR 519 in Seattle I-90 at the Idaho state line [3][9][10][11]

Auxiliary Interstate Highways

Route number Length Western / southern terminus Eastern / northern terminus Counties Description References
I-205 10.57 miles (17.01 km) I-205 at the Oregon state line I-5 in Salmon Creek Clark I-205 starts on the Glenn L. Jackson Memorial Bridge over the Columbia River at the Oregon state line in Vancouver. From Vancouver, I-205 goes northwest to I-5 in Salmon Creek. [3][12]
I-405 30.30 miles (48.76 km) I-5 / SR 518 in Tukwila I-5 / SR 525 in Lynnwood King, Snohomish I-405 starts at I-5 near the SeaTac International Airport in Tukwila. I-405 goes east to Renton, where it intersects with SR 167. Then, it goes north to Bellevue, where it intersects I-90 and SR 520 before going northwest to I-5 in Lynnwood. [3][13]
I-605 I-605 is an oft-proposed, but never constructed bypass of I-405 and I-5. [14]
I-705 1.50 miles (2.41 km) I-5 / SR 7 in Tacoma Schuster Parkway in Tacoma Pierce I-705 begins at I-5/SR 7 and goes north to the Schuster Parkway. [3][15]
I-182 15.19 miles (24.45 km) I-82 / US 12 near Richland US 12 / US 395 in Pasco Benton, Franklin I-182 starts at I-82/US 12 near the Tri-Cities before joining US 12 and going east to Pasco, where the freeway ends at the US 395/US 12 interchange. [3][16]

Notes

  1. ^ The mileage is a sum of the lengths listed and cited on this page.

References

  1. ^ "April 1 Official Population Estimates" (PDF). Washington Office of Financial Management. April 1, 2010. http://www.ofm.wa.gov/pop/april1/rank.pdf. Retrieved November 17, 2010. 
  2. ^ State Highway Log, pp. 217–312
  3. ^ a b c d e f g Washington State Department of Transportation. Washington State Highways (Map). 1:842,000 (2008–2009 ed.). http://www.wsdot.wa.gov/NR/rdonlyres/87105CAD-83A9-49A7-80F3-5719637C1E2D/0/FrontMapBig.pdf. Retrieved November 17, 2010. 
  4. ^ Google, Inc. Google Maps – I-5 (Map). Cartography by Google, Inc. http://maps.google.com/maps?f=d&source=s_d&saddr=I-5+N&daddr=I-5+N&hl=en&geocode=FfgfuAIdICiw-A%3BFVm26wIdc-Su-A&mra=dme&mrcr=0&mrsp=1&sz=14&sll=48.998691,-122.755909&sspn=0.016781,0.055189&ie=UTF8&ll=47.606163,-119.904785&spn=4.414929,14.128418&z=6. Retrieved November 17, 2010. 
  5. ^ "1941 - 1960". Centennial Timeline. Washington State Department of Transportation. http://www.wsdot.wa.gov/Centennial/1941-1960.htm. Retrieved 18 November 2010. 
  6. ^ State Highway Log, pp. 690–718
  7. ^ Google, Inc. Google Maps – I-82 (Map). Cartography by Google, Inc. http://maps.google.com/maps?f=d&source=s_d&saddr=US-97+S&daddr=I-82+E&hl=en&geocode=FaiwzAIdvyPR-A%3BFWPbvAId2zDj-A&mra=dme&mrcr=0&mrsp=1&sz=12&sll=45.930379,-119.313583&sspn=0.07116,0.220757&ie=UTF8&z=12. Retrieved November 17, 2010. 
  8. ^ WSDOT History p. 15
  9. ^ State Highway Log, pp. 719–388
  10. ^ Google, Inc. Google Maps – I-90 (Map). Cartography by Google, Inc. http://maps.google.com/maps?f=d&source=s_d&saddr=Unknown+road&daddr=I-90+E&hl=en&geocode=FZ4z1gIdHnW1-A%3BFfzJ1wIdwA4G-Q&mra=dme&mrcr=0&mrsp=1&sz=11&sll=47.671861,-117.173996&sspn=0.137786,0.441513&ie=UTF8&ll=47.45038,-119.575195&spn=2.213947,7.064209&z=7. Retrieved November 17, 2010. 
  11. ^ WSDOT History p. 7
  12. ^ State Highway Log, pp. 1222–1226
  13. ^ State Highway Log, pp. 1406–1422
  14. ^ Singer, Natalie (July 15, 2004). "State study revives idea of new Western Washington highway". The Seattle Times (The Seattle Times Company). http://seattletimes.nwsource.com/html/localnews/2001979989_corridor15e.html. Retrieved November 6, 2010. 
  15. ^ State Highway Log, pp. 1718–1719
  16. ^ State Highway Log, pp. 1173–1178

Works cited

Current
Proposed