Predecessor highways Highway (now
SR 821), seen shortly after opening in 1924|alt=A black and white photograph of a concrete highway curving along a river and railroad in a narrow canyon Several sections of I-82 follow railroads and wagon roads that were built in the late 19th century to connect towns in
Washington Territory, generally following early Indian trails. In the 1880s, the
Northern Pacific Railway constructed a railroad along the Yakima River between Ellensburg and
Pasco as part of its transcontinental route to
Tacoma via
Stampede Pass. The section through Yakima River Canyon between Ellensburg and North Yakima (now Yakima) bypassed an early
toll road constructed by settler Jacob Durr that traveled farther west via Wenas Valley and Shushuskin Canyon. In 1909, the Washington state government appropriated funds to survey routes through the Yakima Valley as part of a potential extension of the state road system. In 1913, at the suggestion of
good roads advocates, the
Washington State Legislature established the
Inland Empire Highway as one of the trunk routes of its state highway system and appropriated $301,000 (equivalent to $ in dollars) to construct it to modern standards. The highway incorporated several existing and planned county roads from Ellensburg to Pasco; it then continued eastward to
Walla Walla and northward to
Spokane and the Canadian border near
Kettle Falls. The Durr toll road was bypassed by a new highway through the Yakima River Canyon that opened on September 12, 1924, and was fully paved in 1932. and the
federal numbered highway system created in 1926. Under the federal system, the Ellensburg–Yakima section formed part of
US 97, a north–south route through central Washington and Oregon, and the Yakima–Walla Walla portion became part of
US 410, which connected
Aberdeen to
Lewiston, Idaho. In 1923, the Washington state government renumbered the Inland Empire Highway as State Road 3, which would carry over as
Primary State Highway 3 (PSH 3) in 1937. The federal highway system was expanded in the 1930s with an extension of
US 395 along
US 730 from the Tri-Cities towards
Pendleton, Oregon and continuing southward. A branch highway between PSH 3 and the Columbia River near
Plymouth—across from
Umatilla, Oregon—was added to the state highway system in 1943 as an extension of
PSH 8—the North Bank Highway; it was renumbered to
SR 12 in 1964 and later
SR 14 in 1967. The Plymouth extension connected to the
Umatilla Bridge, a
toll bridge that was built downstream from the
McNary Dam in 1955.
Planning and early disputes The Ellensburg–Pendleton corridor was authorized in 1956 but was not formally added to the Interstate system until October 17, 1957. The corridor was proposed by the
Department of Defense and Washington senator
Warren Magnuson in part to connect military facilities in the
Puget Sound region to the
Hanford Site and the
Umatilla Chemical Depot. Its inclusion was initially opposed by Oregon, fearing the loss of truck traffic bound for the
Intermountain West through
Portland. Under the initial plan approved by the Washington state government in January 1958, the highway would travel through the Yakima Valley and cross the Columbia River at
Boardman, Oregon, bypassing the Tri-Cities region entirely. It was numbered "Interstate 82" in 1958, re-using an older designation for what would become
Interstate 80N (now I-84). In 1959, the Washington State Highway Commission requested that the interstate would follow US 410 across
Naches Pass to
Tacoma and
Aberdeen, but the proposal was quietly abandoned. The routing of the freeway's northwestern half was subject to disputes, namely the bypassing of the Yakima River Canyon that was favored by truckers due to its gentler
grades. In 1965, state highway commissioners chose the eastern route through the
Yakima Firing Center, primarily because of its cost and room to support four lanes. A land transfer for from the U.S. Army was approved by Congress in November 1967 to allow for freeway construction near the firing center. A section of the Yakima River Freeway was also planned to pass through part of the
Yakama Indian Reservation but the
Yakama Nation refused to allow the
condemnation of belonging to its members and filed suit against the state government in 1969. The
U.S. District Court and
U.S. 9th Circuit Court of Appeals both ruled in favor of the Yakamas, forcing I-82 to be rerouted across the river on non-reservation land. I-82's chosen route between
Union Gap and
Granger would pass through of the Yakima River's flood plain, attracting criticism from the federal
Environmental Protection Agency for its potential effects on the area. The Yakima County government also disliked the routing, arguing that it would destroy hundreds of acres of prime agricultural land. A later attempt by environmentalists to move the freeway farther away from the river, including a potential route along the
Rattlesnake Ridge, was rejected by the state shorelines
hearings board in 1978 due to its extra distance and potential effects on a rare butterfly bog.
Tri-Cities routing dispute '' in 1974 showing routes considered for I-82 and later I-182|alt=A black-and-white map of freeway routes in the Tri-Cities region of Washington and Umatilla County, Oregon, with various options highlighted and numbered. The routing of I-82's southern half was altered several times during the planning process, which lasted until the early 1970s. Due to complications with the construction of a crossing at Blalock Island that was favored by the
Port of Morrow, Oregon leaders lobbied for the interstate to cross farther east at the existing Umatilla Bridge. The Prosser–Umatilla route remained the favored alignment for both states in the early part of the process of identifying alternatives, despite growing opposition from business leaders in the Tri-Cities and
Walla Walla who sought an interstate connection. In 1962, the Washington highway commissioner ordered a new routing study for the I-82 corridor after hearing requests from legislators in the Tri-Cities area. The study produced four general corridors, including alternatives that shifted I-82 closer to the Tri-Cities, traversed the area, and continued southeastward along
Lake Wallula. The states remained committed to the Umatilla crossing and formally approved the Horse Heaven routing after a two-day public hearing in October 1963. The Tri-Cities and Wallula routes were rejected, in part because of the limited supply of miles allotted by Congress to the Interstate program. Senator Magnuson and Oregon congressman
Al Ullman intervened during the federal approval of the routing and called for a re-study. Magnuson later proposed a bill to add to the Interstate system, including an allotment for the Tri-Cities, but it failed to advance beyond Congressional committees for several years before quietly excluding I-82. In 1968, the federal government authorized $25 million in funding (equivalent to $ in dollars) for the addition. The new study was funded jointly by the two states and contracted to an independent firm that completed it in September 1966. The study recommended that I-82 be routed through
Pasco and follow Lake Wallula to a junction with I-80N near Pendleton, Oregon legislators, particularly those representing the Umatilla area, remained opposed to the routing and accused Washington of trying to "pick-pocket" traffic bound for Oregon. The Washington State Highway Commission gave preliminary approval to the Wallula route in December 1967, with support from the regional director of the Bureau of Public Roads, but their Oregon counterpart remained opposed. Oregon governor
Tom McCall met with Senator Magnuson to propose a compromise route that would serve the Tri-Cities and the
Port of Umatilla, which would later form the basis of a new study begun in mid-1968. In May 1969, the
Federal Highway Administration (FHWA), the successor to the Bureau of Public Roads, announced a new compromise proposal, routing I-82 through Umatilla and adding a spur route
I-182 to serve the Tri-Cities. The Washington State Highway Commission approved the compromise in July 1969, but the Oregon delegation expressed its support of the Wallula routing after it was modified to terminate farther west near
Stanfield. The FHWA approved the Wallula alignment in October 1971, but protests from environmentalists over potential harm to local wildlife areas, including the
McNary National Wildlife Refuge, forced the plan to be reconsidered in early 1973. The Oregon commission remained opposed to all options that bypassed the Umatilla Bridge, mirroring public opinion from hearings in Pendleton, while the Washington commission considered a narrowed set of options around Umatilla that were both opposed by the Tri-Cities and Walla Walla. Support for the Wallula routing from the Tri-Cities waned in late 1973, allowing for a revival of the I-182 compromise proposed by the FHWA. The Washington commission approved a compromise route along the Horse Heaven Hills connecting Kennewick to the Umatilla Bridge, along with the I-182 spur to the Tri-Cities, in October 1973 and the Oregon commission approved it that December. The Washington state government also created a new state highway, SR 143, that connected the Umatilla Bridge to Plymouth. The FHWA approved the routing decision but as late as 1978, attempts were made to propose new alignments for the freeway in Oregon.
Construction and opening The first section of I-82 to open was the eastern bypass of Yakima, which was planned as an upgrade to PSH 3 in the 1950s and completed in November 1963. The bypass freeway was later extended southward to
Union Gap in August 1965 and northward to Selah in August 1967. The section between Ellensburg and Yakima was funded earlier than scheduled, money being diverted from stalled freeway projects in the Seattle area, and construction began in October 1968. The $35 million freeway project (equivalent to $ in dollars) required the excavation of approximately 20 million cubic yards () of dirt and facilitated the discovery of a new
geologic fault that would be monitored for seismic movement. WSDOT contractors built the longest concrete
arch spans in North America on the
Fred G. Redmon Bridge, which crosses Selah Creek near the city of the same name. Major construction in the Yakima Valley began in 1977 with the building of a $5 million section (equivalent to $ in dollars) between
Zillah and Granger, and a bypass of Prosser estimated to cost $7.2 million (equivalent to $ in dollars). Freeway construction was accelerated for sections bypassing the worst stretches of US 410, including winding highways or high-traffic roads. The Zillah–Granger freeway opened in January 1979, and the Prosser bypass opened in late August the same year. I-82 was then extended westward from Prosser to
Grandview in January 1981 at a cost of $19 million. A connection between the existing Yakima Freeway at Union Gap and the Zillah freeway was completed on November 24, 1981, and cost $47 million to construct (equivalent to $ in dollars). The freeway's construction created an embankment between the Yakima River and surrounding areas, which helped to worsen major floods; it also required the digging of several gravel pits nearby, which were later converted into seven trout-stocked ponds that feed a local
osprey population. The last section of the Yakima Valley Freeway to be built, running from Granger to
Sunnyside and Grandview, was opened to traffic on October 29, 1982, shortly after a dedication ceremony to commemorate the Yakima Valley project. , which now carries the eastbound lanes of I-82, seen from the Oregon side|alt=A pair of long bridges crossing a river as seen from the shore The routing of I-82 around the Tri-Cities and to the Umatilla Bridge was approved by the Benton County government in 1972, generally following
SR 14 and bypassing Kennewick to the southwest. Construction on I-82 and I-182 began in 1980, using $340 million (equivalent to $ in dollars) in newly earmarked funds from the U.S. Congress. A short, section bypassing Plymouth and preparing for the new Umatilla Bridge was opened to traffic on August 31, 1981, and cost $5 million to construct (equivalent to $ in dollars). The remaining sections on SR 14 between Plymouth and Kennewick were constructed and paved between 1983 and 1985. US 395 was re-aligned onto the new freeway in 1985, replacing an earlier alignment that traveled through
Wallula, while SR 14 was truncated to Plymouth and SR 143 was eliminated. The final section of I-82 within Washington state, spanning from
Kiona to an interchange south of Kennewick, was dedicated on February 23, 1986, and opened the following month. During construction of I-82, a pair of fossilized tusks belonging to a
mastodon and
Columbian mammoth were found by workers near Kiona and Plymouth, respectively, and were excavated by local archaeologists. The existing divided highway between Prosser and Kiona, built in 1960, was upgraded to Interstate standards in 1987 at a cost of $19.2 million (equivalent to $ in dollars). Construction of the northbound Umatilla Bridge, located upriver from the original bridge, began in 1985. The new bridge cost $16.5 million (equivalent to $ in dollars) and was completed in October 1987 after two years of construction. The final section of I-82, extending between Umatilla and Hermiston, began construction in February 1984 and was dedicated and opened to traffic on September 20, 1988. It was also the final segment of the Interstate Highway system in Oregon, which spanned . The southbound Umatilla Bridge underwent a major $5.2 million (equivalent to $ in dollars) rehabilitation project and re-opened in July 1990. The total cost to construct I-82 was estimated in 1988 to be $317 million (equivalent to $ in dollars), of which $288 million (equivalent to $ in dollars) was spent in Washington and $29 million (equivalent to $ in dollars) was spent in Oregon.
Later years I-80N was renumbered to
I-84 in 1980 as part of a mandate by
American Association of State Highway and Transportation Officials to eliminate
suffixed routes and reduce traveler confusion. The designation of I-82 fell outside the standard numbering scheme for Interstates, which uses comparatively higher numbers for the northernmost east–west routes. A 1970s proposal to renumber I-82 to remain in compliance with the numbering scheme was rejected by the Washington State Department of Highways due to the cost of sign replacement and potential for public confusion. In 1999, the
Oregon Legislative Assembly passed a bill directing ODOT to study a proposal for an extension of I-82 to the
California or
Nevada border. The proposal included the potential use of
road tolls to finance the new freeway, but it was later dismissed by ODOT. The I-82 extension study was completed two years later and outlined three general routes that would replace existing north–south highways in eastern Oregon. The westernmost route would follow
US 97 from
Klamath Falls through
Bend and
Redmond to
Biggs Junction, relying on I-84 to complete its connection with I-82. A variation of the route with a direct connection to I-82 near Hermiston would branch off at
Madras and travel northeastward through a mountainous region along
Route 218 and
Route 207. The easternmost route would follow
US 395 between the California border and Pendleton, passing through a less-densely populated region but serving
Burns and
John Day. The study found that a new freeway would have little effect on economic growth in eastern Oregon and congestion relief in the
Willamette Valley, but would provide a suitable alternative route for long-haul travel. The
Valley Mall interchange in Union Gap was rebuilt from 2009 to 2011 using a series of roundabouts and a loop ramp to replace the existing freeway ramps. In 2010, two overpasses carrying I-82 were demolished and replaced with new structures that would accommodate a future widening project. A separate proposal in the early 2010s included a third lane for I-82 in northern Yakima, but it was postponed in favor of the building of a new interchange and east–west road at the
Cascade Mill development site. A proposal to add
climbing lanes for trucks on the steep grades in the Manastash Ridge between Ellensburg and Yakima was made in the 2000s and remains unfunded . I-82's current interchange with
SR 224 in Kiona was rebuilt in 2016 and will be supplemented with a new interchange serving the
Red Mountain AVA. Construction of the new interchange, which was intended to divert traffic bound for the winery region and new development near West Richland, was proposed by local politicians in the early 2000s but failed to earn funding from the state. The project was postponed in September 2019 after federal officials stated that the traffic volumes would be too low to justify an interchange. ==Exit list==