A casino, also known as a gambling hall or a gaming house, is a place where people gamble. Most casinos are licensed and regulated by the state where they operate. The successful ones rake in billions of dollars each year for the companies, investors, and Native American tribes that own and operate them. Local, state, and national governments also reap substantial revenues in the form of taxes and fees.

Casinos go to extraordinary lengths to lure and keep patrons, relying on sophisticated design and lighting techniques, scents, and sounds to create stimulating environments. For example, computer-designed slot machines feature simulated payouts and noises such as the cling clang of coins dropping. The sound and color schemes are designed to appeal to specific types of patrons, such as the young and old, male and female, and affluent and nonaffluent.

Gambling is a social activity, and most people who go to casinos do so with friends or family. In a poll conducted for the American Casino Association in 2002, 82% of casino patrons reported that they went to a casino as part of a social or entertainment outing.

Most casinos are based in large cities, and they typically feature numerous games and a wide variety of restaurants and bars. In the United States, the biggest casinos are usually located in Atlantic City, Las Vegas, and Reno. A smaller number of casinos are situated on Native American reservations, which are exempt from state antigambling laws. In addition, a few casinos are built in remote locations such as islands in the Caribbean.