Interstate 90 in Washington
Interstate 90 is highlighted in red
|Maintained by WSDOT|
|Length:||296.92 mi (477.85 km)|
|Mountains to Sound Greenway - I-90|
|West end:||I‑5 / SR 519 in Seattle|
| I‑405 in Bellevue
I‑82 / US 97 near Ellensburg
US 395 near Ritzville
US 2 in Spokane
US 195 in Spokane
|East end:||I‑90 at Idaho state line|
Interstate 90 (I-90), a transcontinental Interstate Highway from Seattle, Washington, to Boston, Massachusetts, crosses the state of Washington before crossing the Idaho state line between Spokane and Post Falls. It serves the cities of Seattle, Bellevue, Issaquah, Ellensburg, Moses Lake, Ritzville, and Spokane.
It is the only Interstate Highway to cross the state east to west, but there are two U.S. Routes that also do the same, U.S. Route 2 and U.S. Route 12, along with a few state highways. I-90 is also the only highway in Washington to connect the two largest cities in the state (Seattle and Spokane). The road is the third busiest in the state, behind I-5 at 240,000 and I-405 at 201,000. An estimated 148,000 motorists use the road daily.
I-90 incorporates two of the longest floating bridges in the world, the Lacey V. Murrow Memorial Bridge and the Homer M. Hadley Memorial Bridge, which cross Lake Washington from Seattle to Mercer Island, Washington. They are the second- and fifth-longest such bridges, respectively.
Seattle to Snoqualmie Pass
Interstate 90 starts at the intersection of SR 519 and 4th Ave S in Downtown Seattle. The recently rebuilt freeway joins the I-90 Express Lanes and goes east to an interchange with I-5. After leaving the interchange, the highway travels through the Central Area and into the Mount Baker Tunnel, a tunnel on the National Register of Historic Places that carries I-90 and its express lanes under the Mount Baker neighborhood. After emerging from the eastern portal of the tunnel, I-90 splits and the eastbound lanes go on the Lacey V. Murrow Memorial Bridge and the westbound lanes exit off the Homer M. Hadley Memorial Bridge, which is shared with the I-90 express lanes, both over Lake Washington.
After crossing Lake Washington, I-90 enters Mercer Island and goes under the Mercer Island Lid at West Mercer Way and emerges at 76th Avenue SE before leaving Mercer Island to cross over Lake Washington again on the shorter East Channel Bridge into Eastside. Once in Eastside, the highway enters Bellevue and travels east to Bellevue Way, where the express lanes merge with I-90 or keep going to exit off to I-405.
After leaving a stack interchange with I-405 north of the Factoria Mall, the freeway passes Bellevue College, Lake Sammamish, and Lake Sammamish State Park before entering Issaquah and intersecting SR 900.
After passing by downtown Issaquah, the highway goes along the northern boundary of the Tiger Mountain State Forest and passes Preston, where the speed limit raises from 60 MPH to 70 MPH, before intersecting SR 18 in Upper Preston. From Upper Preston, I-90 passes Echo Lake and Snoqualmie before entering North Bend, where SR 202 begins after an interchange with the highway.
Seattle-Bellevue Express Lanes
Interstate 90 has a 7.45-mile (11.99 km) long reversible express lane that goes across Lake Washington from Seattle to Bellevue. The express lane starts at two different locations, one at the southern terminus of the Downtown Seattle Transit Tunnel and the other at a signalled intersection at 5th Avenue S., S. Dearborn Street, and Airport Way S. The lanes turn east and travel in a separated right-of-way before traveling towards the middle of I-90 east of the interchange with I-5. This section is bi-directional, containing two lanes separated by a barrier, and allows buses to use the lanes in both directions at all times. From there, the lanes travel through the Mount Baker Tunnel and onto the Homer M. Hadley Memorial Bridge, sharing the bridge with the westbound lanes. From there, the lanes travel through Mercer Island and ends at its terminus with the I-90 interchange with Bellevue Way, with ramps connecting to mainline I-90 and I-405.
Segments of the express lanes between the western terminus and I-90 ramps and Island Crest Way and the eastern terminus are reserved for HOV only. The westbound traffic uses the express lanes from 1 am to 12:30 pm (Monday–Friday) The eastbound traffic uses the express lanes from 2 pm to 12 midnight (Monday–Friday) and all day from Saturday to Sunday. The express lanes are closed every other Tuesday from 10 am to 1:30 pm.
Snoqualmie Pass to Ritzville
Forty-two miles east of Bellevue, at milepost 53, I-90 traverses the Cascade Mountains via Snoqualmie Pass, elevation 3,022 feet (921 m), the only interstate crossing and lowest east–west crossing in Washington State. I-90 then goes out towards the Columbia Plateau, passing through the cities of Cle Elum and Ellensburg, where it intersects with Interstate 82. It crosses the Columbia River on the Vantage Bridge. After passing into Grant County, North Frontage Road and South Frontage Road parallel I-90 through Grant County. The frontage roads intersect each exit off I-90 (Exits 143 to 174 and Exits 179 to 184). In Moses Lake at Exit 174, the frontage roads end. The freeway passes through Moses Lake. The frontage roads begin again at Exit 179 in Moses Lake and end at the Adams County line.
Ritzville to Idaho
At Ritzville, I-90 forms a concurrency with US 395 towards Spokane, where US 2 also forms a concurrency and both US 395 and US 2 branch off from I-90 at Downtown Spokane. I-90 continues to head east through the suburbs of Spokane and into Idaho.
As part of the state's first connected state highway system, the Washington State Legislature designated the Sunset Highway between Seattle and Idaho in 1913. Later in 1915, the Legislature also designated the North Central Highway between Ellensburg and Davenport. The State Highway Board selected two routes that would partially connect the main cities of Western Washington to Eastern Washington and Idaho. In 1923, by which time the entire road had been improved and a new connection had filled in a small gap, the Sunset Highway became State Road 2 (Primary State Highway 2 after 1937), but retained its name. The North Central Highway became State Road 7 (Primary State Highway 7 after 1937), but retained its name. Another highway, named Primary State Highway 18 between George and Ritzville. By that time, most of the route of Interstate 90 became US 10, which was established in 1926. Until 1940, the route headed south from Seattle to Renton, then east to Issaquah, in order to travel around Lake Washington.
Interstate 90 crosses Lake Washington between Seattle and Bellevue on a pair of floating bridges that are two of the world's longest floating bridges. The westbound lanes travel on the Homer M. Hadley Memorial Bridge, the fifth longest floating bridge, and the eastbound lanes travel on the Lacey V. Murrow Memorial Bridge, the second longest floating bridge. The Lacey V. Murrow Memorial Bridge, originally called the Lake Washington Floating Bridge, opened on July 2, 1940. The bridge sank during construction on November 25, 1990. It was later rebuilt and the new bridge opened later in 1993. The second bridge, the Homer M. Hadley Memorial Bridge, opened on June 4, 1989.
Later in 1956, President Dwight D. Eisenhower signed the Federal-Aid Highway Act of 1956 which started the construction of Interstate Highways. By 1969, US 10 was removed from the system entirely. During the construction of the freeway between Seattle and Bellevue, lawsuits were filed on May 28, 1970 and stopped construction of Interstate 90 until the early 1990s. Legally, the Washington section of I-90 is defined at Washington Revised Code § 47.17.140. In 1998, I-90 from Seattle to Thorp was designated the Mountains to Sound Greenway to protect its outstanding scenic and cultural resources.
Before 2003, Interstate 90 used to end at a signalled intersection with 4th Avenue S. However, increasing traffic from Downtown Seattle, Colman Dock, Safeco Field, and Qwest Field forced city, county, and state officials to look for improvements to the area. The first stage of the improvements, the SR 519 South Seattle Intermodal Access Project, included the construction of a new on-ramp to Interstate 90 via a new interchange with 4th Avenue S. and Edgar Martínez Drive S. (formerly S. Atlantic Street). Other projects are currently ongoing and have been completed in the recent years on I-90.
|King||Seattle||0.00||0.00||—||Edgar Martínez Drive South, South Atlantic Street||Westbound exit and eastbound entrance|
|0.00||0.00||—||SR 519 north / 4th Avenue South – Seattle City Center, Amtrak, Ferries, Safeco Field, CenturyLink Field||Westbound exit and eastbound entrance|
|0.32||0.51||2||I‑5 – Vancouver, Tacoma, Portland||Signed as exits 2A (south) and 2B (north) eastbound and 2B (south) and 2C (north) westbound|
|1.39||2.24||3||Rainier Avenue||Signed as exits 3A (south) and 3B (north) westbound; no westbound entrance|
|1.58||2.54||—||Express Lanes||Eastbound exit and westbound entrance|
|Lake Washington||2.13||3.43||Lacey V. Murrow Memorial Bridge and Homer M. Hadley Memorial Bridge|
|Mercer Island||4.09||6.58||6||West Mercer Way||Eastbound exit and westbound entrance|
|4.91||7.90||7A||77th Avenue Southeast||Eastbound exit and westbound entrance|
|5.02||8.08||—||80th Avenue Southeast||HOV only; westbound exit and eastbound entrance|
|5.17||8.32||7B||Island Crest Way||Signed as exit 7 westbound|
|6.38||10.27||—||Express Lanes||Westbound exit and eastbound entrance|
|6.41||10.32||8||East Mercer Way|
|Lake Washington||6.78||10.91||East Channel Bridge|
|7.98||12.84||10A||I‑405 – Everett, Renton||Signed as exit 10 westbound|
|8.23||13.24||10B||Richards Road – Factoria||Eastbound exit and westbound entrance|
|9.09||14.63||—||142nd Place Southeast||HOV only|
|9.60||15.45||11B||148th Avenue Southeast – Bellevue College||Westbound exit is via 156th Avenue|
|9.60||15.45||11A||150th Avenue Southeast, 156th Avenue Southeast||Signed as exit 11 westbound|
|11||161st Avenue Southeast||Eastbound exit is via 150th Avenue|
|11.73||18.88||13||West Lake Sammamish Parkway, Lakemont Boulevard Southeast, Southeast Newport Way|
|Issaquah||13.89||22.35||15||SR 900 west (17th Avenue Northwest) – Renton|
|15.20||24.46||17||Front Street, East Lake Sammamish Parkway Southeast|
|16.13||25.96||18||East Sunset Way, Highlands Drive|
|18.32||29.48||20||High Point Way|
|20.59||33.14||22||Preston, Fall City|
|23.72||38.17||25||SR 18 west / Snoqualmie Parkway – Auburn, Tacoma|
|25.40||40.88||27||Snoqualmie, North Bend||Eastbound exit and westbound entrance|
|North Bend||28.63||46.08||31||SR 202 west – North Bend, Snoqualmie|
|30.95||49.81||32||436th Avenue Southeast|
|33.06||53.20||34||468th Avenue Southeast|
|36.14||58.16||38||—||Eastbound exit and westbound entrance|
|37.96||61.09||38||—||Westbound exit and eastbound entrance|
|43.91||70.67||45||USFS Road 9030|
|46.09||74.17||47||Denny Creek, Asahel Curtis|
|Snoqualmie Pass||50.58||81.40||52||SR 906 – West Summit, Alpental||Eastbound exit and westbound entrance|
|Kittitas||51.29||82.54||53||East Summit, Snoqualmie Pass Recreational Area|
|53.03||85.34||54||SR 906 – Hyak, Gold Creek||Access to SR 906|
|61.30||98.65||62||Stampede Pass, Lake Kachess|
|62.31||100.28||63||Cabin Creek Road|
|68.63||110.45||70||Sparks Road – Easton|
|72.34||116.42||74||West Nelson Siding Road|
|76.35||122.87||78||Golf Course Road|
|78.60||126.49||80||Roslyn, Salmon la Sac|
|84||Cle Elum, South Cle Elum|
|84.15||135.43||85||SR 903 north / SR 970 – Cle Elum, Wenatchee|
|91.91||147.91||93||Elk Heights Road|
|99.36||159.90||101||Thorp Highway – Thorp|
|104.35||167.94||106||US 97 north – Ellensburg, Wenatchee||West end of US 97 overlap|
|Ellensburg||107.65||173.25||109||I‑90 Bus. (Canyon Road) – Ellensburg|
|109.15||175.66||110||I‑82 east / US 97 south – Yakima||East end of US 97 overlap|
|134.72||216.81||136||Huntzinger Road – Vantage|
|Columbia River||135.72||218.42||Vantage Bridge|
|Grant||136.08||219.00||137||SR 26 east to SR 243 – Othello, Pullman, Richland|
|148.07||238.30||149||SR 281 north – Quincy, Wenatchee, George|
|150.02||241.43||151||SR 283 north / SR 281 north (via SR 281 Spur) – Ephrata, Soap Lake, Quincy, Wenatchee|
|Moses Lake||172.89||278.24||174||Hansen Road – Mae Valley|
|173.69||279.53||175||Westshore Drive – Mae Valley||Westbound exit only|
|174.28||280.48||176||I‑90 Bus. east / SR 171 north – Moses Lake|
|177.74||286.04||179||SR 17 / I‑90 Bus. west – Moses Lake, Ephrata, Othello|
|181.12||291.48||182||O Road Northeast/Southeast – Wheeler|
|183.18||294.80||184||Q Road Northeast/Southeast|
|187.18||301.24||188||U Road Northeast/Southeast – Warden|
|Adams||195.20||314.14||196||Deal Road – Schrag|
|205.13||330.12||206||SR 21 – Lind, Odessa|
|220||US 395 south – Ritzville, Pasco||Western end of US 395 overlap|
|219.67||353.52||221||SR 261 south – Ritzville, Washtucna|
|Lincoln||Sprague||242.98||391.04||245||SR 23 – Sprague, Harrington|
|Spokane||255.41||411.04||257||SR 904 east – Tyler, Cheney|
|262.02||421.68||264||SR 902 east – Cheney, Medical Lake|
|268.27||431.74||270||SR 904 west – Four Lakes, Cheney|
|270.53||435.38||272||SR 902 west – Medical Lake|
|274.04||441.02||276||I‑90 Bus. east – Spokane, Geiger Field|
|275.45||443.29||277B||US 2 west – Spokane Airport, Fairchild AFB, Davenport||Western end of US 2 overlap; signed as exit 277 westbound|
|275.92||444.05||277A||Garden Springs||Signed as exit 277 westbound; no entrance ramps|
|Spokane||277.06||445.88||279||US 195 south – Colfax, Pullman|
|277.88||447.20||280A||Maple Street||Signed as exit 280 eastbound|
|280B||Lincoln Street||Eastbound exit is via exit 280|
|279.05||449.09||281||US 2 east / US 395 north (Division Street) – Newport, Colville||Eastern end of US 2/US 395 overlap|
|279.83||450.34||282A||SR 290 east (Trent Avenue) / Hamilton Street||Signed as exit 282 eastbound|
|280.08||450.75||282B||Second Avenue||Westbound exit only|
|281.44||452.93||283B||Thor Street, Freya Street|
|Spokane–Spokane Valley city line||282.05||453.92||—||Havana Street||Eastbound entrance only|
|Spokane Valley||283.32||455.96||285||Sprague Avenue||No eastbound entrance|
|287.56||462.78||289||SR 27 (Pines Road)|
|288.74||464.68||291A||Evergreen Road – Spokane Valley Mall|
|Liberty Lake||292.63||470.94||294||Country Vista Drive, Appleway Avenue||Westbound exit and eastbound entrance|
|293.89||472.97||296||Liberty Lake, Otis Orchards|
|297.20||478.30||299||State Line, Idaho|
|297.52||478.81||I‑90 east||Continuation into Idaho|
|1.000 mi = 1.609 km; 1.000 km = 0.621 mi
Reversible express lanes
The entire route is in King County.
|Seattle||1.99||3.20||—||Airport Way South, South Dearborn Street||HOV entrance and exit only|
|2.21||3.56||—||Downtown Seattle Transit Tunnel||Bus only|
|3.21||5.17||—||Rainier Freeway Station||Bus only|
|3.66||5.89||—||I‑90 west to I‑5||Westbound off-ramp only (All Mercer Island SOVs exit here)|
|3.87||6.23||—||I‑90 east||Eastbound on-ramp only (All Mercer Island SOVs enter here)|
|Mercer Island||6.58||10.59||7A||77th Avenue SE|
|6.80||10.94||7B||Island Crest Way||All Mercer Island SOVs enter or exit here|
|7.45||11.99||7C||80th Avenue SE||HOV entrance and exit only; this reversible ramp was converted to an HOV-only entrance onto the eastbound outer roadway in early 2012|
|8.01||12.89||—||I‑90 west||Westbound HOV entrance only|
|8.39||13.50||—||I‑90 east||Eastbound HOV exit only|
|Bellevue||8.90||14.32||—||I‑405||Eastbound HOV entrance only|
|9.44||15.19||9||Bellevue Way||HOV entrance and exit only|
|1.000 mi = 1.609 km; 1.000 km = 0.621 mi
- "Route Log and Finder List - Interstate System: Table 1". FHWA. Retrieved 2007-08-05.
- Washington State Department of Transportation, State Highway Log, 2006
- Washington State Department of Transportation (2008). Official State Highway Map (Map). 1:842,000. Official State Highway Maps. Cartography by U.S. Geological Survey (2008–2009 ed.). Olympia, Washington. http://www.wsdot.wa.gov/NR/rdonlyres/87105CAD-83A9-49A7-80F3-5719637C1E2D/0/FrontMapBig.pdf. Retrieved 2008-08-07.
- GM Johnson (2007). Washington Large Print (Map). GM Johnson Large Print State Maps (2007 ed.). Burnaby, British Columbia. http://store.maplink.com/map.aspx?nav=MS&cid=10056,10078&pid=538387. Retrieved 2008-08-08.
- Google Maps (2008). U.S. Route 2 Overview Map (Map). Cartography by NATVEQ.
- Google Maps (2008). U.S. Route 12 Overview Map (Map). Cartography by NATVEQ.
- Google, Inc. "Interstate 82 Overview Map". Google Maps (Map). Cartography by Google, Inc. http://maps.google.com/maps?f=d&saddr=I-82+W%2FUS-395+N+%4045.931720,+-119.328370&daddr=46.970999,-120.511265&hl=en&geocode=6148851770216159538,45.931720,-119.328370&mra=mi&mrsp=1,0&sz=14&sll=46.967485,-120.514698&sspn=0.017747,0.035706&ie=UTF8&ll=46.452997,-120.135498&spn=2.293271,4.570312&z=7. Retrieved 2008-07-31.
- Google, Inc. "Interstate 90 Overview Map". Google Maps (Map). Cartography by Google, Inc. http://maps.google.com/maps?f=d&saddr=47.592396,-122.32549&daddr=I-90+E+%4047.696497,+-117.042762&hl=en&geocode=6567855726850209615,47.592420,-122.325970%3B6664985198082853012,47.696497,-117.042762&mra=dme&mrcr=0&mrsp=0&sz=18&sll=47.592674,-122.325742&sspn=0.001096,0.002232&ie=UTF8&ll=47.487513,-120.563965&spn=4.49854,9.140625&z=6. Retrieved 2008-07-31.
- Washington State Department of Transportation (2007). "Washington Annual Average Daily Traffic Data". Retrieved 2008-08-26.[dead link]
- "National Register Information System". National Register of Historic Places. National Park Service. 2010-07-09.
- GM Johnson (2006). Seattle Map Book (Map). City Street Maps (2006 ed.). Burnaby, British Columbia. http://store.maplink.com/map.aspx?nav=MS&cid=10056,10078&pid=522983. Retrieved 2008-09-13.
- United States Department of Transportation. "Preliminary List of Nationally and Exceptionally Significant Features of the Interstate Highway System". Retrieved 2008-09-20.
- GM Johnson (2008). Bellevue, Redmond, Kirkland, Sammamish (Map). City Street Maps (2008 ed.). Burnaby, British Columbia. http://store.maplink.com/map.aspx?nav=MS&cid=10056,10078&pid=522906. Retrieved 2008-09-13.
- Washington State Department of Transportation. "WSDOT Interchange Viewer - Interstate 90 (Exit 2B to 22)". Retrieved 2008-09-13.
- Google Maps (2008). Map of I-90 (Seattle to Snoqualmie Pass) (Map). Cartography by NATVEQ.
- Rand McNally (2008). The Road Atlas (Map). p. 108. ISBN 0-528-93961-0.
- Rand McNally (2008). The Road Atlas (Map). p. 110. ISBN 0-528-93961-0.
- Washington State Department of Transportation. "WSDOT Interchange Viewer - Interstate 90 (Exit 25 to 78)". Retrieved 2008-09-13.
- Google Maps (2008). Map of I-90 (Seattle-Bellevue Express Lanes) (Map). Cartography by NATVEQ.
- Washington State Department of Transportation (2006). WSDOT I-5 Express Lane Map (Map). http://www.wsdot.wa.gov/Northwest/King/ExpressLanes/I5map.htm. Retrieved 2008-08-08.
- Washington State Department of Transportation. "King County Express Lanes - Schedule". Retrieved 2009-01-31.
- Go Northwest!. "Snoqualmie Pass in the Cascade Mountains of Washington". Retrieved 2008-08-24.
- Google Maps (2008). Map of I-90 (Snoqualmie Pass to Ritzville) (Map). Cartography by NATVEQ.
- Washington State Department of Transportation. "WSDOT Interchange Viewer - Interstate 90 (Exit 80 to 149)". Retrieved 2008-09-13.
- Washington State Department of Transportation. "WSDOT Interchange Viewer - Interstate 90 (Exit 151 to 215)". Retrieved 2008-09-13.
- Google Maps (2008). Map of I-90 (Ritzville to Idaho) (Map). Cartography by NATVEQ.
- GM Johnson (2005). Spokane City Pearl (Map). Pearl City Maps (2005 ed.). Burnaby, British Columbia. http://store.maplink.com/map.aspx?nav=MS&cid=10056,10078&pid=522965. Retrieved 2008-09-13.
- GM Johnson (2007). Spokane (Map). City Street Map (2007 ed.). Burnaby, British Columbia. http://store.maplink.com/map.aspx?nav=MS&cid=10056,10078&pid=522985. Retrieved 2008-09-13.
- GM Johnson (2007). Inland Empire (Map) (2007 ed.). Burnaby, British Columbia. http://store.maplink.com/map.aspx?nav=MS&cid=10056,10078&pid=522933. Retrieved 2008-09-13.
- Washington State Department of Transportation. "WSDOT Interchange Viewer - Interstate 90 (Exit 220 to 279)". Retrieved 2008-09-13.
- Washington State Department of Transportation. "WSDOT Interchange Viewer - Interstate 90 (Exit 280 to 299)". Retrieved 2008-09-13.
- Washington State Legislature (1913). "An act relating to public highways, classifying the same and naming and fixing the routes of certain state roads.". Session Laws of the State of Washington. Olympia, WA: State of Washington. 1913 chapter 65, p. 221.: "A highway starting from the Pacific Highway at Renton, Washington; thence over the most feasible route by the way of Snoqualmie Pass into the Yakima River Valley; thence by way of Wenatchee, over the most feasible route, through Waterville and Spokane, to the state boundary, which shall be known as the Sunset Highway."
- Washington State Legislature (1913) . "65". Session Laws of the State of Washington. Session Laws of the State of Washington (1913 ed.). Olympia, Washington: Washington State Legislature. p. 221. Retrieved 2008-08-10.
- State Highway Board, Road Map of Washington Showing Main Traveled Roads, 1912
- State Highway Board, Map of Washington State Highways Authorized by Legislative Acts of 1913[dead link] (with 1915 changes marked)
- Rand McNally, Official 1923 Auto Trails Map[dead link], District No. 14: Washington, Oregon, Northern California, Western Idaho
- Washington State Legislature (1923). "An act relating to, classifying, naming and fixing the routes of certain state highways, amending Section 6796, and repealing Sections 6791, 6792, 6793, 6794, 6795, 6797, 6798, 6799, 6800, 6801, 6802, 6803, 6804, 6805, 6806, 6808, 6809, 6811, 6812, 6813 and 6816 of Remington's Compiled Statutes.". Session Laws of the State of Washington. Olympia, WA: State of Washington. 1923 chapter 185, p. 628.: "A primary state highway, to be known as State Road No. 2 or the Sunset Highway, is established as follows: Beginning at the City of Seattle; thence by the most feasible route in an easterly direction through the cities of Renton, North Bend, Cle Elum, Wenatchee, Waterville, Davenport and Spokane to the Washington-Idaho state line."
- Washington State Legislature (1937). "An act relating to public highways, creating and establishing, describing and designating the primary state highways of the State of Washington and declaring an emergency.". Session Laws of the State of Washington. Olympia, WA: State of Washington. 1937 chapter 190, p. 941.: "A primary state highway to be known as Primary State Highway No. 18 is hereby established according to description as follows: Beginning at the wye junction on Primary State Highway No. 7, near Burke, thence in an easterly direction by the most feasible route by way of Neppel to a junction with Primary State Highway No. 11 at Ritzville."
- United States Department of Agriculture. "Final 1926 Plan of the U.S. Highway System" (November 11, 1926). Retrieved on August 10, 2008.
- Department of Highways, Highway Map: State of Washington, Revised to April 1, 1933
- Department of Highways, Highways of the State of Washington (Rand McNally), 1939
- Washington State Department of Transportation. "WSDOT - History of WSDOT (1921-1940)". Retrieved 2008-08-11.[dead link]
- Washington State Department of Transportation. "WSDOT - History of WSDOT (1978-1990)". Retrieved 2008-08-11.[dead link]
- Washington State Department of Transportation. "WSDOT - History of WSDOT (1991-2004)". Retrieved 2008-08-11.[dead link]
- United States Department of Transportation/Federal Highway Administration (2006-07-07). "The Greatest Decade 1956-1966 Part 1 Essential to the National Interest". Retrieved 2008-08-11.
- United States Department of Transportation/Federal Highway Administration. "History of the Interstate Highway System". Retrieved 2008-08-11.
- Washington State Department of Transportation. "WSDOT - History of WSDOT (1967-1977)". Retrieved 2008-08-11.[dead link]
- Washington State Legislature. "RCW 47.17.140: State route No. 90 — Washington green highway". Retrieved 2008-08-10.
- "Mountains To Sound Greenway (Washington)". Retrieved 2008-08-24.
- Washington State Department of Transportation. "WSDOT - Construction Projects on Interstate 90". Retrieved 2008-08-11.
- "Changes ahead for I-90 Express Lanes". Washington State Department of Transportation. 2012-01-18. Archived from the original on 2014-07-10. Retrieved 2015-01-02.
|Wikimedia Commons has media related to Interstate 90 in Washington.|
- Interstate 90 @ Interstate-Guide.com
- Western Terminus of Interstate 90 @ Interstate-Guide.com
- Highways of Washington State