Interstate 84 in Utah

Interstate 84 marker
Interstate 84
Map
I-84 highlighted in red
Route information
Maintained by UDOT
Length117.38 mi[1] (188.90 km)
Existed1977–present
NHSEntire route
Major junctions
West end I-84 at Idaho state line
Major intersections I-15 near Tremonton
US 91 in Brigham City
I-15 in Riverdale
US 89 in Uintah
East end I-80 near Echo
Location
CountryUnited States
StateUtah
CountiesBox Elder, Weber, Davis, Morgan, Summit
Highway system
  • Utah State Highway System
SR-83 SR-85

Interstate 84 (I-84) is a part of the Interstate Highway System that links Portland, Oregon, to I-80 near Echo, Utah. The 117.38-mile-long (188.90 km) segment in the US state of Utah is the shortest of any of the three states the western I-84 passes through and contains the eastern terminus of the highway. I-84 enters Box Elder County near Snowville before becoming concurrent with I-15 in Tremonton. The concurrent highways travel south through Brigham City and Ogden and separate near Ogden-Hinckley Airport. Turing east along the Davis County border, I-84 intersects US Route 89 (US-89) and enters Weber Canyon as well as Morgan County. While in Morgan County, I-84 passes the Devil's Gate-Weber Hydroelectric Power Plant and Devil's Slide rock formation. Past Morgan, the highway crosses into Summit County, past the Thousand Mile Tree before reaching its eastern terminus at I-80 near Echo.

Construction of the controlled-access highway was scheduled in late 1957 under the designations Interstate 82S (I-82S) and Interstate 80N (I-80N). The I-82S designation was only applied on paper for about a year, but the I-80N designation was the highway's official designation until 1977 when it was renumbered I-84 by the American Association of State Highway and Transportation Officials (AASHTO). By 1986, construction of the freeway had been completed across the three states. Average traffic in 2012, along the non-concurrent parts of I-84, ranged from as few as 6,655 vehicles traveling along I-84 at the interchange with State Route 86 (SR-86) in Henefer, and as many as 18,945 vehicles used the highway at the SR-26 interchange in Riverdale.

  1. ^ "Table 1: Main Routes of the Dwight D. Eisenhower National System Of Interstate and Defense Highways". FHWA Route Log and Finder List. Federal Highway Administration. December 31, 2021. Retrieved August 7, 2022.