Interstate 405 Oregon
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.
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
Source: December 31, 2021 Interstate Route Log and Finders List
I-405 Annual Average Daily Traffic (AADT)
North End – Portland, Oregon
North East at
North West at
South End / Marquam Bridge – Portland, Oregon
South East at
- Interstate 50th Anniversary: The Story of Oregon’s Interstates.
Page updated November 6, 2020.