Interstate 405 Washington

Interstate 405 Washington
Tukwila, WA ↔ Lynnwood, WA•30.30 miles

Overview

I-405 north - Bellevue, WA
Interstate 405 north at Downtown Bellevue, Washington. 06/27/15

Interstate 405 provides a bypass to the east of Seattle, connecting with several major suburbs on the east shore of Lake Washington. The urban loop is the most direct route to Redmond, home of Microsoft, via the freeway along State Route 520. As a result of growth in the greater Seattle area, Interstate 405 carries significant traffic volume, almost on a level like I-405 in California, albeit with fewer lanes.

Mileage by State

Washington30.30 mi

Data Sources

December 31, 2025 Interstate Route Log and Finders List

High Priority Corridor

Interstate 405 is part of High Priority Corridor 35: FAST Corridor.

History

The original proposal for Interstate 405 around greater Seattle was submitted to the American Association of State Highway Officials (AASHO) in a letter dated July 14, 1958.1 Initial stretches were designated as Washington State Route 405 between Renton and Tukwilla. The first section opened to traffic in September 1965. SR 405 was redesignated as I-405 with its completion by 1971.2

Seattle inset on the 1967 Washington Official Highway Map
Interstate 405 completed north to Bellevue on the 1967 Official Washington Highway Map.
1967 AAA map for Seattle, Washington
Interstate 405 temporary designated as State Route 405 north of Bellevue in 1967
I-90/405 trailblazers on SR 518
State named trailblazers for I-5 and I-405 along the eastbound entrance ramp to SR 518 from Seattle-Tacoma International Airport (SEA). Photo by Jeff Royston (02/24/06).
SR 509 south at SR 518 - Burien, WA
SR 509 south at the eastbound on-ramp for SR 518 to Seattle-Tacoma International Airport (SEA) and I-5/405. Photo by Chris Elbert (03/03/06).

North End Interstate 5 Washington State Route 525 ‐ Lynnwood, WA

Interstate 405 North at Interstate 5 Washington State Route 525

I-405 north one mile from I-5 at Alderwood Manor, Washington

Interstate 405 weaves northward between the Alderwood Manor and Martha Lake communities 2.9 miles from SR 527 to SR 525 and I-5. 07/19/23

I-405 north one mile from I-5 at Alderwood Manor, Washington I-405 north next meets I-5 north to Everett, Washington I-405 north transitions to SR 525 in a half mile at I-5 and Lynnwood, WA I-405 north at I-5/SR 525 - Martha Lake, WA I-405 north at I-5/SR 525 - Lynwood, WA I-405 north at I-5/SR 525 - Lynwood, WA

Washington State Route 525 South at Interstate 5 Interstate 405

SR 525 south passes under 164th St SW on the 1.5 miles to I-5/405

1.5 miles north of I-5 south and I-405 south on SR 525 at North Lynnwood. 07/20/23

SR 525 south passes under 164th St SW on the 1.5 miles to I-5/405 SR 525 heads a half mile south from Alderwood Mall Pkwy to I-5/405 SR 525 runs along the Lynnwood city line southeast to I-5/405 SR 525 south at I-5 south to Seattle, Washington SR 525 end and I-405 begin shields posted above Interstate 5

Interstate 5 South at Interstate 405

I-5 south at Martha Lake, Washington two miles from I-405/SR 525

Interstate 5 advances south through a six-ramp parclo interchange (Exit 183) with 164th Street SW at Martha Lake ahead of I-405. 07/19/23

I-5 south at Martha Lake, Washington two miles from I-405/SR 525 I-5 south at 164th St SW, one mile from I-405/SR 525 at Martha Lake, WA I-5 converges with I-405/SR 525 south at Exit 182 in a half mile Exit 182 provides access only to I-405 south from I-5 south

Interstate 5 North at Interstate 405 Washington State Route 525

I-5 north 1.5 miles ahead of I-405/SR 525 at Lynwood, Washington

I-5 advances 1.5 miles northeast from 44th Avenue W (SR 525 Spur) in Lynwood to the systems interchange (Exit 182) with SR 525 north and I-405 south. 07/20/23

I-5 north 1.5 miles ahead of I-405/SR 525 at Lynwood, Washington I-5 north at SR 524, a half mile from I-405 in Lynnwood, WA I-5 continues north from SR 524 in Lynwood, WA to I-405/SR 525 I-5 north at Alderwood Mall Pkwy and Exit 182 to I-405/SR 525 Exit 182 separates from I-5 north for I-405 south and SR 525 north

North End – Past Views

Past Views Gallery (Tap to Expand / Collapse Section)

Interstate 405 North at Interstate 5 Washington State Route 525

I-405 north one mile from I-5/SR 525 in 2006

Sign replacements made one mile from I-5 on I-405 removed the pull through panel for SR 525 north and added Everett for the exit to I-5 north. 08/29/06

I-405 north one mile from I-5/SR 525 in 2006 I-405 north spans SR 524 just ahead of I-5 at Lynnwood, Washington I-405 north at I-5 north to Everett, Washington in 2006

Interstate 5 South at Interstate 405 Washington State Route 525

I-5 south at Exit 183 and Martha Lake, Washington in 2006

Guide signs at Exit 183 were relocated from a sign bridge onto the overpass linking the HOV lanes with the Ash Way Park & Ride facility. 08/30/06

I-5 south at Exit 183 and Martha Lake, Washington in 2006 I-5 south at Interstate 405 south to Bothell, WA in 2006

Washington State Route 525 South at Interstate 5 Interstate 405

SR 525 south at I-5/405 in 2006

The HOV lane for I-5 south was removed. Replacement of the I-405 pull through panel removed the HOV reference and Bellevue. 08/29/06

Interstate 5 North at Interstate 405 Washington State Route 525

I-5 north at 44th Ave W (SR 524 Spur), two miles from I-405/SR 525

Exit 181 A connects I-5 with 44th Avenue W to SR 524 in Lynwood just ahead of Alderwood Mall and two miles from I-405/SR 525. 08/30/06

I-5 north at 44th Ave W (SR 524 Spur), two miles from I-405/SR 525 I-5 north a half mile ahead of I-405/SR 525 in 2006 I-5 north at I-405 south and SR 525 north in 2006

South End Interstate 5 Washington State Route 518 ‐ Tukwila, WA

Interstate 405 South at Interstate 5 Washington State Route 518

I-405 south enters Tukwila from Renton, WA, one mile from I-5/SR 518

Interstate 405 south concludes at a cloverstack interchange with I-5 and SR 518. 07/19/23

I-405 south enters Tukwila from Renton, WA, one mile from I-5/SR 518 I-405 advances west from SR 181 and Christensen Rd to I-5/SR 518 I-405 arcs west between Tukwila Pkwy and Southcenter Blvd to I-5/SR 518 61st Ave S spans I-405 at the HOV exit for I-5 north in Tukwila, WA Ramps for I-5 and adjacent Southcenter Blvd depart I-405 south I-405 south ends at the ramp for I-5 south. SR 518 extends 3.40 miles west

Washington State Route 518 East at Interstate 5 Interstate 405

Ramps from Airport Expwy tie into SR 518 one mile from I-5/405 at SeaTac, WA

International Boulevard (SR 99 south) spans SR 518 east at the exchange with Airport Expressway from Seattle-Tacoma International Airport (SEA), one mile from I-5/405 at Tukwika. 07/20/23

Ramps from Airport Expwy tie into SR 518 one mile from I-5/405 at SeaTac, WA SR 518 east enters Tukwila, WA ahead of I-5 and I-405 north. SR 518 parallels the SoundTransit 1 Line east to I-5/405 in Tukwila, WA SR 518 meets I-5/405 beyond the exit for 51st Ave S/Westfield Southcenter SR 518 east becomes I-405 north at the systems exchange with I-5 in Tukwila, WA

Interstate 5 North at Interstate 405 Washington State Route 518

I-5 north at I-405/SR 518 - Tukwila, WA

The ensuing exit along I-5 northbound links with parallel Southcenter Parkway at Westfield Southcenter mall. Exit 154 immediately follows for SR 518 and I-405. 06/24/15

I-5 north at I-405/SR 518 - Tukwila, WA I-5 north at I-405/SR 518 - SeaTac, WA I-5 north at I-405/SR 518 - Tukwila, WA I-5 north at I-405/SR 518 - Tukwila, WA

Interstate 5 South at Interstate 405 Washington State Route 518

I-5 converges with SR 599, 1.5 miles from I-405 in Tukwila, WA

The southbound HOV lane along I-5 separates from the freeway mainline just ahead of the wye interchange with SR 599. The exchange (Exit 154 A) with Interstate 405 follows. 07/20/23

I-5 converges with SR 599, 1.5 miles from I-405 in Tukwila, WA S 144th St spans I-5 one mile from I-405/SR 518 in Tukwila, Washington I-5 south at SR 518 west and I-405 north in Tukwila, Washington I-5 south at at Left Exit 154 A for I-405 north to Renton, Washington

South End – Past Views

Past Views Gallery (Tap to Expand / Collapse Section)

Interstate 405 South at Interstate 5 Washington State Route 518

I-405 south at I-5/SR 518 - 2006

An end sign for Interstate 405 was formerly posted at the transition into SR 518 west. Photo by Chris Elbert (03/03/06).

Interstate 5 South at Interstate 405 Washington State Route 518

I-5 south one mile from I-405/SR 518 in 2006

Previous overheads for Exit 154 B to SR 518 west and Exit 154 A for I-405 north at the S 144th Street overpass in Tukwila. 08/29/06

I-5 south one mile from I-405/SR 518 in 2006 I-5 south at Exit 154 B for SR 518 west in 2006 I-5 south at Exit 154 A to I-405 north in 2006

References

  1. Washington State Highway Commission letter to AASHO, dated July 14, 1958, retrieved from AASHTO Route Numbering Archive.
  2. Interstate 405 (Washington). AARoads Wiki.
Updated February 1, 2024