I-15

Interstate 15, commonly abbreviated I-15 and colloquially known as the Long 15 is a pre-War Interstate Highway that passes through the former states of Montana, Idaho, Utah, Arizona, Nevada, and California, stretching from the border with annexed Canadian territories to San Diego County, close to the Mexican border.

Background
Before the Great War, the I-15 was one of the most important freight routes, stretching from San Diego all the way to Canada. After the war, while much of the highway network eventually fell to disrepair, the I-15 remained a silent monument to the might of the United States. In the late 23rd century, heirs of the United States, the New California Republic, integrated the I-15 into the Mojave Campaign as the primary supply route into the Mojave Wasteland. The one hundred mile stretch of the Interstate passing through solid desert was filled with troops, traders, tourists, and travelers journeying to and from the Mojave and lands beyond. By 2281 it is the single most important strategic road in the Mojave, a lifeline for NCR forces deployed on the front against the Legion. The shutting down of the I-15 as a result of the NCRCF prison break in early 2281, caused by Powder Ganger attacks on caravans and the deathclaw infestation at Quarry Junction (caused by the Gangers when they stole the dynamite from Sloan) has hurt commerce and limited military movements in the Mojave, as traders are forced to take a detour to New Vegas using Highway 93 through Nipton and Novac.

Layout
The Long 15 begins all the way back on the Pacific coast, in San Diego (Dayglow), connecting it to the rest of the Republic. The most vital stretch of the I-15 in 2281 begins with the hundred mile highway between Barstow and the Mojave Outpost south of the Clark Mountain Range, before continuing into the Ivanpah Valley and the Ivanpah Dry Lake. It crosses into Nevada at Primm, then continues north through the desert, straight to New Vegas. Several small settlements lay on both sides of the Interstate as it makes its way north, including Goodsprings and Sloan.

It enters the Las Vegas Valley between Quarry Junction and Black Mountain, entering the city limits of Henderson and Las Vegas proper. It runs through a trench on the outskirts, before transitioning to an elevated highway near the Las Vegas Strip and continues in parallel until it exits Las Vegas in the northeast, near Nellis Air Force Base. It then continues towards Salt Lake City in Utah, passing shortly through Arizona, before continuing towards Ogden and further into Idaho, Montana, and Canada.

Appearances
The I-15 appears only in Fallout: New Vegas