A casino is a building or room where people can engage in gambling. It is a popular form of entertainment, and it is legal in some jurisdictions. People may gamble through table games, such as blackjack and roulette, or through card games, such as poker. The profits from these activities are the primary source of revenue for many casinos. In the United States, casinos are located in cities such as Atlantic City, New Jersey; Las Vegas, Nevada; and Chicago, Illinois. Some casinos are also found on American Indian reservations, which are exempt from state antigambling laws.

A large casino resort, such as the Venetian in Las Vegas, offers luxurious rooms and suites and a vast array of dining, shopping, and entertainment choices, including world-class live music and comedy. A casino can also be a destination in its own right, as is the case with Caesars Palace, which has hosted residencies for stars such as Frank Sinatra, Elton John, Madonna, and Cher.

The casino industry is sensitive to the potential for cheating and stealing, which can occur both in collusion between patrons and among staff members. In addition to traditional security measures, casinos employ a variety of technology to prevent these actions. For example, many casinos feature catwalks that allow surveillance personnel to look down through one-way glass at the tables and machines. Other technologies include video cameras, motion sensors, and fingerprint recognition software. Some casinos also have special programs to discourage underage gambling.