State Route 184 was created in 1963, running north from US-89A/91A at North Temple and State Streets around the west side of the State Capitol and back to SR-1 north of downtown. The roadway had previously been part of SR-181 since 1935, but with US-89A/91A moving from South Temple to North Temple, a new number was needed to avoid a one-block overlap. SR-184 remained a separate route until 2007, when North Temple west of State Street was given to Salt Lake City for the Airport extension of the TRAX Green Line. Since North Temple had carried US-89 east of 300 West, that route was realigned to use what had been SR-186 on 300 West and 400 South, cutting SR-186's west end back to 400 South and State Street. But that intersection was also the south end of SR-184, and SR-186 was extended to absorb SR-184.