A casino is a facility where gambling takes place. It is also an establishment that allows customers to play casino games, such as poker and blackjack, in exchange for cash or other items of value (such as food and drink).

The United States has the largest number of casinos, with the most prominent being located in Las Vegas, Nevada; Atlantic City, New Jersey; and Chicago, Illinois. Some casinos are also located on American Indian reservations and are not subject to state antigambling laws.

Modern casinos use a variety of technology to monitor and prevent cheating. For example, in table games such as blackjack and roulette, electronic systems record the exact amount of money wagered minute-by-minute, and computers alert dealers and supervisors to any anomalies. In addition, random number generators ensure that all players have the same odds of winning, reducing the opportunity for cheating.

In the past, casinos often offered free alcohol and food to their customers, but this practice has been increasingly curtailed due to concerns about problem gambling. Many casinos now provide support services and hotlines for those who need assistance.

Before visiting a casino, it is important to check the local gambling laws. Currently, most US states allow gambling, but regulations vary. Some states only permit certain types of gambling, while others limit the age at which people can gamble to 21 years or older. Moreover, some states have different rules on how much a person can bet.