Before the mid-20th century, 300 West was confusingly known as Second West, based on the idea of numbering streets from the nearest corner of Temple Square rather than just from the southeast corner (which is the only origin recognized by the modern Salt Lake County addressing system).

From 1967 to 1969, SR-176 started at an intersection with SR-171 in South Salt Lake only about a block east of I-15 and proceeded straight north as a four-lane (plus, as of 2012, a center turn lane) road without continuous sidewalks (300 West continues south of this point before swerving east to avoid crossing the FrontRunner and Union Pacific railroad corridor (Rio Grande's Utah Division during the 1960s) at an acute angle and connects to a short frontage road of 3900 South, but was never a state highway).

[1] 300 West passes under I-80 about a mile north of SR-171, and then crosses the TRAX Green Line (originally Rio Grande's line to Park City) before intersecting SR-201 (2100 South), the first major east-west street north of 3300 South, and enters Salt Lake City.

Due to the east-west traffic and the easy access from the major freeway crossing just to the west, this area has many big box stores (as of 2012).

Just a few yards (meters) north of the rail crossing, the street passes under the long elevated ramps connecting the concurrent interstates 15 and 80 to West Temple, SR-270.

North of the intersection with 400 South next to Pioneer Park, 300 West now carries US-89; for the description of the last four- or five-block stretch of former SR-176, see US-89 (UT).