A casino is a gambling establishment, where people can gamble on games of chance or skill. Most modern casinos offer a wide variety of casino games, including roulette, baccarat, blackjack, and video poker. Some also offer a number of restaurant and nightclub options. Casinos are generally located in cities with large populations and/or tourists. Many American casinos are operated on Native American reservations, where they are not subject to state antigambling laws.

Most modern casinos have a security department that employs both physical and specialized surveillance personnel. These departments usually patrol the casino and respond to calls for assistance or reports of suspicious or definite criminal activity. Casino security also monitors the operation of casino-owned slot machines and table games using closed circuit television cameras.

Some casinos have catwalks that extend above the floor, allowing surveillance personnel to look down on the activities of players through one-way mirrors. This allows the casinos to monitor player behavior and make changes to game rules, if necessary. Casinos may also hire gaming mathematicians to analyze game statistics and develop strategies for limiting losses. They may also contract with companies that specialize in mathematically optimizing slot machine algorithms to maximize their profits. In addition, some casinos have an internal research and development department to create new games that can attract customers and generate revenue.