|Las Vegas started as a stopover on the pioneer trails to the west, and became a popular railroad town in the early 1900s. It was a staging point for all the mines in the surrounding area, especially those around the town of Bullfrog, that shipped their goods out to the rest of the country. With the proliferation of the railroads, Las Vegas became less important but the completion of the nearby Hoover Dam in 1935 resulted in the growth of residents and tourism. The dam, located 30 mi (48 km) southeast of the city, also formed Lake Mead, the world's largest man-made lake and reservoir. Today, tours are offered into lesser known parts of the dam. The legalization of gambling in 1931 led to the advent of the casino-hotels, for which Las Vegas is famous. Major development occurred in the 1940s. The success of the city's early casino businesses was owed to American organized crime. Most of the original large casinos were managed or at least funded under mob figures Benjamin "Bugsy" Siegel, Meyer Lansky or other mob figures at this time. The rapid growth of this gambling empire is credited with dooming Galveston, Texas; Hot Springs, Arkansas; and other major gaming centers in the 1950s.|
American aviator George Crockett, a descendant of frontiersman Davy Crockett, established Alamo Airport in 1942 on the site currently occupied by McCarran International. In 1948, Clark County purchased the airfield from Crockett to establish the Clark County Public Airport, and all commercial operations moved to the site of this airport. On December 20, 1948 the airport was renamed McCarran Field for U.S. Senator Pat McCarran, a longtime Nevada politician who authored the Civil Aeronautics Act and played a major role in developing aviation nationwide.
By this time, the airport was serving 1.5 million passengers a year, the location for the present terminals was moved from Las Vegas Boulevard South to Paradise Road, opening in March 1963. The terminal, designed by Welton Becket and Associates and John Replogle, was inspired by the TWA terminal at JFK. It ultimately became the basis for the United Airlines terminal at O'Hare International Airport seven years later.