A casino is an establishment for certain types of gambling. Casinos are often combined with hotels, resorts, restaurants, retail shops, cruise ships or other tourist attractions. They are also known for hosting live entertainment such as stand-up comedy, concerts and sports. Casinos are usually located in or near urban areas and are designed around a theme. This theme may be based on culture, geographic location or history. The games played in casinos are largely chance-based, with some involving skill. In the United States, most casinos are privately owned and operated by commercial or tribal gaming operators. Most of these operators are licensed by the state and operate under a variety of regulatory frameworks.

In the United States, there are approximately 4,000 commercial casinos. In addition to these private operators, the government operates a few national-level gaming facilities. The largest public casino is in Las Vegas, Nevada. Other major casinos are in Atlantic City, New Jersey; Biloxi, Mississippi; Reno, Nevada; and South Point Hotel & Casino, Colorado Springs, Colorado. In addition to gambling, casinos sometimes offer other forms of entertainment such as stage shows, buffets and night clubs.

Most modern casinos are built with lavish interiors that are meant to create a fantasy-like environment for players. They are brightly colored and often have a high ceiling. Various lighting effects are used to create a mood and to increase player excitement. Many casinos use the color red to stimulate gamblers. The simulated excitement is designed to overcome the essentially random nature of casino gambling.

The mathematical odds of winning any particular game in a casino are always in favor of the house. As a result, it is virtually impossible for players to win money consistently. In addition, the average casino takes a percentage of all bets, which is called the vig or rake. This means that the average gambler loses money over the long term.

Some casinos have a reputation for being glamorous and exciting, while others have a more seedy underbelly. In the past, organized crime groups provided much of the cash for casinos in cities like Reno and Las Vegas. However, mob members were not content with simply funding a gambling enterprise; they sought to control the operations and take sole or partial ownership of casinos in their jurisdictions. They also resorted to violence and intimidation in an attempt to control the outcome of gambling.

In modern times, large casino chains have emerged to compete with the Mafia in attracting upscale clientele. With deeper pockets than the mafia, these companies were able to purchase out the mob interests and run their casinos without the taint of organized crime. In addition, the threat of losing a gaming license at even the slightest hint of mob involvement has forced the mob to retreat from its once-controlling stance in the business. Despite these efforts, mobsters still own and operate some casinos in the United States.