Las Vegas was established in 1835 after a group of settlers received a land grant from the Mexican government. The town was laid out in the traditional Spanish Colonial style, with a central plaza surrounded by buildings which could serve as fortifications in case of attack. Las Vegas soon prospered as a stop on the Santa Fe Trail. During the Mexican-American War in 1846, Stephen W. Kearny delivered an address at the Plaza of Las Vegas claiming New Mexico for the United States.
During the railroad era Las Vegas boomed, quickly becoming one of the largest cities in the American Southwest. Turn-of-the-century Las Vegas featured all the modern amenities, including an electric street railway, the "Duncan Opera House" at the northeast corner of 6th Street and Douglas Avenue, a Carnegie library, the Hotel Castaneda (a major Harvey House), and the New Mexico Normal School (now New Mexico Highlands University).
The arrival of the railroad on July 4, 1879 brought with it businesses, development and new residents, both respectable and dubious. Murderers, robbers, thieves, gamblers, gunmen, swindlers, vagrants, and tramps poured in, transforming the eastern side of the settlement into a virtually lawless brawl. Among the notorious characters were such legends of the Old West as: dentist Doc Holliday and his girlfriend Big Nose Kate, Jesse James, Billy the Kid, Wyatt Earp, Mysterious Dave Mather, Hoodoo Brown, and Handsome Harry the Dancehall Rustler.
Historian Ralph Emerson Twitchell once claimed regarding the Old West, "Without exception there was no town which harbored a more disreputable gang of desperadoes and outlaws than did Las Vegas."
Since the decline and restructuring of the railroad industry began in the 1950s, the city's population has remained relatively constant.