 The highway enters the state in Mohave County northeast of Mesquite and Las Vegas, Nevada, paralleling the old US 91 heading northeast on an alignment north of the Virgin River. I-15 parallels the Virgin River for its entire length in Arizona, but the terrain abruptly becomes more rugged at mile 13, where the Virgin River Gorge begins. The first interchange is exit 8 at Littlefield, where old US 91 turns north to avoid the gorge. I-15 crosses the river for the first time just beyond Littlefield, and soon passes another interchange serving local roads eastwards. This exit, exit 9, is a right-in / right-out design with frontage roads, constructed after the initial opening. Access under I-15 is provided just south of the ramps.
