[citation needed] SR-90 begins in the center of Brigham City and heads east through the east-central portion of the town.

After continuing east for six blocks, the highway veers to the southeast to meet with US-89/US-91 at the mouth of Brigham Canyon, where SR-90 traffic is diverted to US-89/US-91 northbound through a flyover ramp.

[2] 200 South in Brigham City was added to the state highway system in 1910,[3] and in the 1920s it became part of SR-1 (US-91).

[4] A proposed connection from proposed I-15 southwest of Brigham City east and northeast to SR-1 east of Brigham City was numbered State Route 85 in 1960, and in 1962, when SR-1 was moved to I-15, SR-85 was extended along former SR-1 to Idaho.

[6] The entire route is in Brigham City, Box Elder County.