| ||For the location in the Fallout: New Vegas add-on Lonesome Road, see Long 15.|
As a whole, the freeway travels northeast, beginning at Dayglow in California, through the Mojave Wasteland and New Vegas, before heading into Arizona and Utah. The interstate comes close to Zion National Park and goes through Salt Lake City (New Jerusalem) and Ogden (New Canaan). It then continues on through Idaho and Montana and becomes Alberta Highway 4 upon crossing into Canada.
In 2281, I-15 is a four-lane freeway for the entire length through the Mojave Wasteland. It connects New Vegas to the territories of the NCR and is a major trade route for caravans. The New California Republic has jurisdiction over the highway south of Nellis Air Force Base. According to the New Vegas map, the freeway enters the wasteland near an NCR base called "Long 15," only accessible if the Courier decides to launch nukes toward the NCR at the conclusion of Lonesome Road.
The highway travels northeast toward the Mojave Outpost before running northbound into the valley under the Ranger Unification Treaty monument. At the foot of the hill, it meets the western terminus of Nipton Road (Nevada State Route 164), with its reststop to the west. It then travels alongside the Ivanpah Dry Lake to Primm and the California Sunset Drive-in. It continues north into Powder Ganger territory, where a number of their camps are located. Before turning northeast, it meets with Goodsprings Road (Nevada State Route 160) near Jean Sky Diving.
The highway then runs parallel to the western train tracks as it leaves Powder Ganger territory into Sloan. Continuing northeast, it bypasses Quarry Junction and Black Mountain, leading to the Junction 15 railway station. Deathclaws overrun the part of the highway between Sloan and the railway station, making it difficult for travelers to reach Black Mountain via the freeway.
The road turns right at Hunter's farm, then turns north again as it enters Fiends territory as a narrow trench. The Samson rock crushing plant, New Vegas Steel and the west pump station are all built alongside this part of the freeway, but the nearby staircases must be used to leave the freeway to get to them.
Once the highway reaches just south of New Vegas, it rises out of the trench to become a heavily damaged elevated freeway that cannot be traversed. From here, the freeway continues above parts of Westside, turning east through Freeside where it merges with Highway 93 at a destroyed intersection. Once it leaves the New Vegas area, it turns north outside the western edge of Nellis Air Force Base, toward Arizona. The south cistern, Freeside's north gate, and Fields' shack are all built under this section of the freeway.
- Travelers along the Long 15 have complained to NCR rangers that caravans have been harassed and attacked by fearsome super mutants living in the irradiated ruins of Black Mountain.
- Even though the NCR protects I-15, Highway 95 is a much safer route to take to get to New Vegas, due to deathclaws and other deadly creatures roaming around the town of Sloan.
- If the deathclaws on I-15 are killed, they will not respawn.
- At the ending cutscenes, if the Brotherhood of Steel has been convinced to form a truce with the NCR, they will assist the NCR in patrolling I-15.
- I-15 is also the main trade route headed back to the NCR, and the Hub, is situated on the highway after it exits the Mojave.
Behind the scenesEdit
Interstate 15 is based on the real world Interstate 15.