From Idaho, I-84 enters Utah at a point approximately 7 miles (11.3 kilometers) from Snowville in Box Elder County. It proceeds southeast towards Tremonton where I-84 joins the route of I-15.
Just south, at Corinne, Utah, I-84 joins the route of the First Transcontinental Railroad which the highway follows to the its terminus. I-15/I-84 pass to the west of Ogden where I-84 separates from I-15 and follows the Weber River. As the freeway passes through Weber Canyon it also passes through several small farming communities, including Morgan, where the Browning Arms Company headquarters can be seen from the freeway. Also visible in the canyon is Devil's Slide, an unusual rock formation just off the freeway. [4] Farther up the canyon is the 1000 mile tree, planted by Union Pacific Railroad workers to mark 1000 miles from the railroad's origin in Omaha, Nebraska.[5] The freeway ends at Echo, a near ghost town that before served as a stopover for the railroad, at a junction with Interstate 80. Also near the junction is Echo Reservoir and Echo Dam.