A casino is an establishment for gambling. It provides customers with gaming tables, slot machines, video poker, and other gambling activities. In the United States, casinos are usually regulated by state law and must be licensed. Casinos are sometimes combined with hotels, restaurants, retail shops, and other entertainment facilities. Some casinos offer live entertainment such as concerts or stand-up comedy.

The precise origin of gambling is unknown, but it appears in many societies throughout history. It is generally thought to be based on luck or chance. Modern casino gambling consists of games like blackjack, craps, roulette, baccarat, and video poker, as well as sports betting and pari-mutuel wagering.

In modern casinos, patrons gamble by using chips with built-in microcircuitry that interact with electronic systems to oversee the exact amounts wagered minute-by-minute and warn of any statistical deviation from expected values. Casinos employ mathematicians who specialize in gaming analysis, and they routinely contract with outside experts for this work.

Gambling is a heavily regulated industry, with most states having strict anti-gambling laws. Nevertheless, some states allow casinos in specific locations, such as Atlantic City, New Jersey, or on American Indian reservations, which are exempt from state anti-gambling statutes. In the United Kingdom, licensed and regulated gambling clubs operate casinos in cities such as London and Divonne-les-Bains, France. In the United States, the most famous casino is the Bellagio in Las Vegas. Other notable casinos include the Monte-Carlo, in Monaco, and the Casino Lisboa, in Lisbon, Portugal.