Interstate 84 (Western)
The western Interstate 84 is the primary route linking the northwestern cities of Salt Lake City, Boise and Portland. This one of two instances of Interstate 84; the other runs east from Scranton, Pennsylvania to Sturbridge, Massachusetts via New York and Connecticut.
Interstate 84 in Portland is known as the Banfield Expressway; it is named after a former head of the Oregon Highway Commission. The stretch east from Portland through the Columbia River Gorge is one of the most scenic sections of Interstate Highway in the entire system.
Parallel U.S. Routes
Interstate 84 largely follows U.S. 30 from Portland east to Rupert, Idaho. East of Rupert, U.S. 30 used to split into two branches: U.S. 30N and U.S. 30S. I-84 replaced U.S. 30S from Rupert southeast to Echo Junction via Ogden, Utah.
Idaho and Utah proposed the renumbering of Interstate 80N as Interstate 86, but the Oregon State Transportation Commission turned down the request on May 17, 1977. Reasons cited included costs, which were estimated at $100,000 to replace all of the signs, and also that businesses that were advertised as being along Interstate 80 North would be upset by the need to readvertise their location.1
Idaho also proposed renumbering Interstate 15W as I-84 between I-80N and Pocatello. That was conditionally approved by the American Association of State Highway Officials (AASHTO) as Interstate 86 on July 6, 1977, as Interstate 84 was instead applied to I-80N across Idaho, Oregon and Utah. A Utah Department of Transportation (UDOT) announcement followed on August 13, 1977, indicating that approval was granted by AASHTO to renumber the freeway as I-84. UDOT director Blaine J. Kay said renumbering the route would eliminate confusion between the I-80 mainline in Utah and the northwesterly I-80N, following the transportation officials effort to eliminate duplication of numbers which are modified by letter additions.2 The Idaho Department of Transportation followed with an announcement regarding the AASHTO approval in November 1977. Officials indicated that conversion to I-84 was to be completed prior to July 1, 1980.3
The freeway was completed within Oregon in 1975, but it still had several Super Two sections, including the segments from Boardman (Exit 164) to Stanfield Junction (Exit 188) and the Pendleton Bypass. These segments were upgraded to full Interstate standards with four lanes by 1980.
Within Oregon, Interstate 80N followed Columbia River Highway Number 2, which was also known as Oregon Highway 2. The Interstate was constructed in the Beaver State in stages commencing in 1963. One of the first segments of I-80N to be completed was the section between the city of Portland and The Dalles. This section was largely complete in 1963 but not finalized due to the narrow terrain until 1969. East of The Dalles, U.S. 30 was initially improved to expressway standards in the 1950s, but Interstate upgrades did not begin until after 1966 on this section. The freeway was considered fully constructed on July 3, 1980, with the completion of a segment of freeway near Baker City.4
Interstate 84 follows the Banfield Expressway through Portland. This freeway was constructed prior to the implementation of Interstate standards, and it would have required a costly retrofit to modernize the highway. As a result, a new route was suggested for Interstate 84. The proposed reroute of I-84 through eastern Portland between Interstate 5 and Interstate 205 would have followed the unbuilt “Mount Hood Freeway” instead of the Banfield Expressway. In the mid 1960s, various alternate alignments were considered for the Mount Hood Freeway, which would have been about five miles in length.
The alignment selected for this freeway was known as “Division-Powell” corridor because it was to have followed U.S. 26 (Powell Boulevard). To facilitate connecting the Mount Hood Freeway with existing Interstate 80N east of I-205, a 2.5 mile long overlap with Interstate 205 would be required. In 1968, the Oregon Department of Transportation tried to obtain approval for this proposed routing. As local communities became aware of the freeway’s proposed impact in established neighborhoods, a lawsuit was filed in 1972 in the U.S. District Court. The lawsuit demanded additional corridor studies and a full Environmental Impact Statement for this project.
Oregon – 375.17
Idaho – 275.74
Utah – 117.38*
Source: December 31, 2021 Interstate Route Log and Finders List
* – 35.98 miles on I-15
The last two sections of U.S. 30 to be upgraded to Interstate standards were stretches through Umatilla Indian Reservation and between La Grande and North Powder in eastern Oregon. Additionally a Super-Two portion of freeway ran south from U.S. 30N / OR 201 (Exit 356) to the Idaho state line.
Interstate 80N stretched east from the Oregon state line to Boise and from South Federal Way near Exit 57 to Mountain Home in Idaho. The two sections were linked by late 1969.
Interstate 80N was completed east from U.S. 89, south of Ogden, to Devils Slide by 1969. A stub of I-80N also connected I-15 with SR 26, shown here as U.S. 89 as well, at what is now a SPUI.
As a result of this controversy coupled with the nationwide energy crisis at that time, the Portland City Council voted to withdraw its approval of the Mount Hood Freeway on July 25, 1974. By July 1975, the freeway was withdrawn by the department of transportation, and the Interstate funds were reallocated to other projects.4
Within Idaho, the final section of Interstate 84 built was the stretch through Caldwell. The route formerly took traffic through the middle of the city through what was regarded as an infamous traffic light. With construction of I-84 in the final stages through Caldwell in August 1983, the signal was removed from the corridor. Final paving of the main lanes for the last two mile stretch in Idaho commenced in September, with overall completion of the project in July 1984.5
The Utah stretch of Interstate 84 across Blue Creek Summit was the last to be built along the entire freeway. The 9.8 mile long segment was dedicated on September 25, 1986.6
East End – Echo, Utah
East North at
West South at
West End – Portland, Oregon
West End Throwback
- “Interstate 80 will keep being Interstate 80.” Eugene Register-Guard, May 18, 1977.
- “Interstate 80 to become 84.” The Deseret News, August 13, 1977.
- “Road numbers to change.” The Spokesman-Review, November 3, 1977.
- Interstate 50th Anniversary: The Story of Oregon’s Interstates
- “Caldwell’s ‘claim to fame’ light is gone.” The Deseret News, August 21, 1983.
- “Officials dedicate the final stretch of I-84.” The Deseret News, September 26, 1986.
Page updated July 20, 2021.