A casino (or gambling house) is a place where people can gamble and play games of chance. Many casinos are combined with hotels, restaurants, retail shops and other tourist attractions. Some states have legalized casinos, while others have prohibited them or restricted their operations to licensed locations such as riverboats and Indian reservations.

Most casino games have built in advantages for the casino that ensure its profitability, even if most bets are lost by individual players. This advantage is referred to as the house edge. It is not an arbitrary number: the house edge is calculated by taking into account the expected return on each bet, including money paid to the dealer.

To make up for this edge, casinos use a variety of techniques to attract customers and keep them gambling. Slot machines are designed with bright colors and electronic sounds that appeal to the senses. More than 15,000 miles of neon tubing are used to light up the casinos along the Las Vegas Strip. Casinos are also a major source of revenue for cities and nations where they are located.

The history of the modern casino is a story of shifting social mores and changing economic conditions. The first casinos were established in Nevada, where the booming railroad and tourism industries made it possible to draw people from all over the country. Mob money poured into Reno and Las Vegas in the 1950s, and organized crime figures became involved in casinos, buying up land and buildings or simply renting space for their own games.