Interstate 405 Oregon

Interstate 405 Oregon
Marquam Bridge – Portland, OR ↔ Portland, OR•3.53 miles

Overview

I-405 Fremont Bridge - Portland, OR
The Fremont Bridge from the south bank of the Willamette River in Portland's Northwest District. 08/27/06

The Stadium Freeway, Interstate 405 is a short urban loop encircling Downtown and the Pearl District in Porland west of the Willamette River. I-405 overlaps with U.S. 30 across the Fremont Bridge to I-5 at the Boise and Eliot neighborhoods. The south end of the freeway ties into the Marquam Bridge taking Interstate 5 northeast from the South Waterfront area to East Portland.

U.S. 26 westbound briefly overlaps with I-405 north from the SW 6th Avenue entrance ramp to Exit 1 D for Sunset Highway west. U.S. 26 eastbound follows I-405 south from Sunset Highway to SW Broadway at Exit 1 C. U.S. 26 (Sunset Highway) extends west across the Tualatin Mountains to the city of Beaverton along a freeway.

Mileage by State

Oregon4.25 mi

Data Sources

December 31, 2025 Interstate Route Log and Finders List

History

Construction on the Stadium Freeway began in 1964. Interstate 405 opened south of the Fremont Bridge on February 25, 1969. The tied arch bridge across the Willamette River opened on November 11, 1973. Costing $121 million, I-405 was the single most expensive Interstate Highway construction project in Oregon.2

1965 Gousha Portland, Oregon inset map
1965 Gousha map showing Interstate 405 under construction south of the Portland city center.
Portland inset on the 1968 Oregon Official Highway Map
Interstate 405 completed north to Montgomery Street in Portland on the 1968 Oregon Official Highway Map

North End Interstate 5 U.S. 30 ‐ Portland, OR

Interstate 405 North U.S. 30 East at Interstate 5

I-405/U.S. 30 cross the Fremont Bridge north to I-5 in Portland, OR

U.S. 30 combines with Interstate 405 north along the lower level of the Fremont Bridge to I-5. 09/26/25

I-405/U.S. 30 cross the Fremont Bridge north to I-5 in Portland, OR U.S. 30 turns south from I-405 along I-5 to I-84 east in Portland, OR I-405/U.S. 30 follows the lower level of the Fremont Bridge to I-5 above OR 99W I-405/US 30 north at I-5 south in Portland, Oregon I-405 north ends with two lanes joining I-5 north beyond the spur to Kerby Ave

Interstate 5 South at Interstate 405 Interstate 30

I-5 south at I-405/US 30 - Portland, OR

Traveling south between the Overlook and Boise neighborhoods, one mile ahead of the separation with Interstate 405 (Stadium Freeway). 08/27/06

I-5 south at I-405/US 30 - Portland, OR I-5 south at I-405/US 30 - Portland, OR I-5 south at I-405/US 30 - Portland, OR

Interstate 5 North U.S. 30 West at Interstate 405

I-5/US 30 north at I-405 - Portland, OR

U.S. 30 combines with Interstate 5 north from the west end of I-84 to the Fremont Bridge with I-405 south. 09/02/06

I-5/US 30 north at I-405 - Portland, OR I-5/US 30 north at I-405 - Portland, OR I-5/US 30 north at I-405 - Portland, OR

North End – Past Views

Past Views Gallery (Tap to Expand / Collapse Section)

Interstate 405 North U.S. 30 East at Interstate 5

I-405/U.S. 30 north across the Fremont Bridge in 2015

Previous overheads on the Fremont Bridge northbound referenced U.S. 30 to The Dalles. 06/24/15

I-405/U.S. 30 north across the Fremont Bridge in 2015 U.S. 30 east joins I-5 south from the north end of I-405 in Portland, OR I-405 north at I-5 north and the spur to Kerby Ave in 2016

South End Interstate 5 ‐ Marquam Bridge – Portland, OR

Interstate 405 South U.S. 26 East at Interstate 5

I-405/US 26 south at I-5 - Portland, OR

Southbound I-405 reaches Exit 1C for U.S. 26 east, 6th Avenue, and the Ross Island Bridge just ahead of Interstate 5. 08/27/06

I-405/US 26 south at I-5 - Portland, OR I-405 south at I-5 - Portland, OR I-405 south at I-5 - Portland, OR I-405 south at I-5 - Portland, OR

Interstate 5 North at Interstate 405 U.S. 26

I-5 advances one mile north to I-405 (Stadium Frwy) in Portland, OR

I-5 runs along the South Waterfront adjacent to the Willamette River north toward Interstate 405 and the Portland city center. 07/20/23

I-5 advances one mile north to I-405 (Stadium Frwy) in Portland, OR I-5 north at OR 43, 0.4 miles from I-405 in Portland Oregon Former button copy signs for I-405, U.S. 26 and OR 43 on I-5 northbound I-5/405 northbound split in Portland, Oregon

Interstate 5 South at Interstate 405 U.S. 26

I-5 south at I-405/US 26 - Portland, OR

Southbound Interstate 5 spans the Willamette River across the lower deck of the Marquam Bridge leading directly to I-405 (Stadium Freeway) north. Photo by Doug Kerr (06/07/14).

I-5 south at I-405/US 26 - Portland, OR I-5 south at I-405/US 26 - Portland, OR I-5 south at I-405/US 26 - Portland, OR

References

  1. Oregon Department of Transportation. Retrieved from http://egov.oregon.gov/ODOT/HWY/GEOENVIRONMENTAL/docs/Historic_Bridge/Willamette_Fremont_Bridge.doc
  2. Interstate 50th Anniversary: The Story of Oregon’s Interstates.
Updated October 16, 2025