Main Street (SR 601) begins at an intersection with South Las Vegas Boulevard and Saint Louis Avenue. At the intersection with Oakey Boulevard, former SR 601 becomes a one-way pair; the northbound direction retains the name Main Street, while the southbound direction is signed as Commerce Street. Further north, the pair intersects Charleston Boulevard; furthermore, the eastern terminus of SR 159's central segment is at Commerce Street. Main Street provides access to a pedestrianized Boulder Avenue and the Burlesque Hall of Fame. About 400 feet (120 m) north of Gass Avenue, the one-way pair merges as Main Street. It then provides access to the Carolyn G. Goodman Plaza, the Las Vegas City Hall, and numerous hotels and casinos. The intersection of Main Street and the Fremont Street Experience is the mathematical origin of Las Vegas's street address grid.
Main Street then goes under I-11 / US 93 / US 95 (former I-515) before intersecting Bonanza Road (SR 579, former US 95) and Washington Avenue (unsigned SR 578) before serving as the eastern boundary of the portion of the Las Vegas Paiute Tribe in Las Vegas. After an intersection with Owens Avenue, Main Street (and, thus, former SR 601) ends at a roundabout with Las Vegas Boulevard and North 5th Street.
Main Street is part of the National Highway System (NHS) between Charleston Boulevard and Stewart Avenue. The NHS is a system of highways considered important to the country's defense. The NHS corridor continues along Stewart Avenue until intersecting Las Vegas Boulevard. It turns north to end at I-11.