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.

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.

In 1847, the town was the site of the Battle of Las Vegas, which was a part of the broader Taos Revolt by local Hispanos and Pueblo peoples against United States occupation.

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 Castañeda Hotel (a major Harvey House), and the New Mexico Normal School (now New Mexico Highlands University).

The annual affair included pie eating contests, barbecues, parades, banquets, balls, and "ranch rodeos."

In the early years, celebrities—cowhands as well as big-name bands, movie stars like Tom Mix, and artists such as Randall Davey—came to Las Vegas for this event.

Murderers, robbers, thieves, gamblers, gunmen, swindlers, vagrants, and tramps poured in, transforming the eastern side of the settlement into a virtually lawless brawl.

[12] 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.

In April of 2022, Las Vegas and surrounding areas of San Miguel and Mora counties experienced the Hermit's Peak / Calf Canyon Wildfire.

The most recent figures (2019) as provided by the U. S. Census Bureau estimate the total number of persons (all ages) at or below the poverty line has increased to 35.6%.

It acquires, organizes, preserves and provides access to pertinent information and scholarly materials for curricular needs, intellectual pursuits and personal enrichment of its clientele.

Built from a $10,000 donation from philanthropist Andrew Carnegie, its Neo-Classical Revival architecture resembles Thomas Jefferson's Monticello.

The library sits in the middle of a park that occupies an entire city block, bordered by Victorian-style homes and buildings.

The City of Las Vegas Museum & Rough Rider Memorial on Grand Avenue, dedicated in 1940, was first established by the decision of Theodore Roosevelt's Rough Riders regiment (the first Volunteer Cavalry Regiment of the Spanish–American War), who named Las Vegas its official reunion home.

The museum, free and open to the public, houses a memorial collection of artifacts, archives and photographs from the Rough Riders and mementos in relation to the 1898 Cuban Campaign of the Spanish–American War, with information on over 200 members of the original regiment, RRR Association documents, etc.

The museum illuminates the history of Las Vegas, its connection to the Rough Riders, the Santa Fe Trail and the development of New Mexico.

It features collections of local Native American pottery, household items, costumes, ranching and farming equipment, agricultural and mercantile operations, and home life.