View the below map of Washingotn showing interstate highways, Washington’s interstate highways span approximately 764 miles, connecting major cities, ports, and neighboring states. Key routes include I-5, running 277 miles from Oregon to Canada, I-90, stretching 297 miles from Seattle to Idaho, and I-82, linking eastern Washington with Oregon. These highways play a vital role in supporting commerce, with I-5 alone handling 60% of the state’s freight traffic. Regular maintenance ensures safety and efficiency, making the interstate system essential for economic and daily transportation needs.
View above the map of Washington state showing all the interstate highways spreaded all across the state of Washington, USA.
Interstate Highways in Washington
List of Primary Interstate Highways in Washington
Interstate Highway
Length (miles)
Route Description
Key Cities Connected
Year Established
I-5
277
Runs north-south from the Oregon border near Vancouver to the Canadian border at Blaine.
Seattle, Tacoma, Olympia, Vancouver
1956
I-90
297
Spans east-west from Seattle through Snoqualmie Pass to the Idaho border.
Seattle, Spokane, Ellensburg
1956
I-82
144
Connects the Tri-Cities area with Yakima and the Oregon border.
Yakima, Tri-Cities
1958
I-405
30
A bypass of I-5, running through the eastern Seattle metropolitan area.
Bellevue, Kirkland, Renton
1969
I-705
1.5
A spur connecting I-5 to downtown Tacoma and the Port of Tacoma.
Tacoma
1988
I-182
15
Runs from I-82 to the Tri-Cities, serving as an east-west connector.
Richland, Pasco
1980
I-205
10
A bypass of I-5 near Vancouver, connecting to Portland, Oregon.
Vancouver
1982
List of Auxiliary Interstate Highways in Washington
Interstate Highway
Length (miles)
Type
Route Description
Key Cities Connected
Year Established
I-405
30
Bypass
Runs through the eastern Seattle metropolitan area as a bypass of I-5.
Bellevue, Kirkland, Renton
1969
I-705
1.5
Spur
Connects I-5 to downtown Tacoma and the Port of Tacoma.
Tacoma
1988
I-182
15
Connector
Links I-82 to the Tri-Cities, providing an east-west connection.
Richland, Pasco, Kennewick
1980
I-205
10
Bypass
Acts as a bypass of I-5 near Vancouver, connecting Washington to Portland, Oregon.
Vancouver
1982
Washington Interstate Highways
Introduction to Washington’s Interstate System
Washington state’s interstate highways are a crucial part of the state’s transportation infrastructure, connecting major cities, facilitating commerce, and providing critical links to neighboring states and Canada. The interstate system spans approximately 764 miles, including primary and auxiliary routes, and is a key component of the National Highway System, ensuring efficient transportation of goods and people across the state.
Primary Interstate Highways
Interstate 5 (I-5)
Interstate 5 is the backbone of Washington’s highway system, stretching 277 miles from the Oregon border near Vancouver to the Canadian border at Blaine. It connects major urban centers like Seattle, Tacoma, and Olympia while serving as a primary north-south corridor for both freight and passenger traffic. I-5 also provides access to major ports in Seattle and Tacoma, supporting Washington’s international trade.
Interstate 90 (I-90)
I-90 is the longest interstate in Washington, covering 297 miles. This east-west route begins in Seattle and crosses the Cascade Mountains via Snoqualmie Pass, connecting the Puget Sound region with central and eastern Washington. It provides critical access to cities like Spokane and serves as a vital link to Idaho and beyond.
Interstate 82 (I-82)
Spanning 144 miles, I-82 connects the Tri-Cities area with Yakima and the Oregon border. It plays a significant role in transporting agricultural goods from eastern Washington to other parts of the Pacific Northwest.
Auxiliary Interstate Highways
Interstate 405 (I-405)
I-405 is a bypass of I-5, running 30 miles through the eastern Seattle metropolitan area. It connects key suburbs like Bellevue, Kirkland, and Renton, reducing congestion on I-5 and supporting the region’s growing population.
Interstate 705 (I-705)
I-705 is a short spur route of 1.5 miles that connects I-5 to downtown Tacoma and the Port of Tacoma. This highway supports freight operations and provides access to Tacoma’s city center.
Interstate 182 (I-182)
I-182 spans 15 miles, linking I-82 to the Tri-Cities. This route is an essential east-west connector in southeastern Washington, supporting regional commerce and local traffic.
Interstate 205 (I-205)
I-205 is a 10-mile bypass of I-5 near Vancouver. It provides an alternative route for traffic heading to Portland, Oregon, and eases congestion on the main I-5 corridor.
Economic and Transportation Significance
Washington’s interstate highways are vital to the state’s economy, facilitating the movement of millions of tons of freight annually. I-5 alone handles nearly 60% of the state’s freight traffic, connecting ports, railways, and airports with businesses across the state. The interstates also support tourism, enabling easy access to major destinations like Mount Rainier, Olympic National Park, and Seattle.
Infrastructure and Maintenance
The interstate highways in Washington undergo regular maintenance and upgrades to ensure safety and efficiency. Projects include seismic retrofitting of bridges, road widening to handle increasing traffic, and adding smart technologies to improve traffic management. Federal and state funding supports these initiatives, emphasizing the importance of long-term sustainability for the transportation network.
Key Facts About Washington’s Interstate Highways
Total Interstate Mileage: 764 miles
Longest Interstate: I-90 (297 miles)
Major Cities Connected: Seattle, Tacoma, Spokane, Vancouver, Bellevue, Yakima
Year Established: 1956 under the Federal-Aid Highway Act
Critical Trade Corridors: I-5, I-90, and I-82
Environmental and Social Impact
Efforts are being made to reduce the environmental impact of the interstate system in Washington. Projects include the implementation of electric vehicle charging stations along major routes, reducing emissions from freight vehicles, and enhancing public transit connections to reduce dependency on cars. These initiatives aim to balance the state’s transportation needs with its commitment to environmental sustainability.
