A casino is a gambling establishment that offers games of chance. It can be a large resort complex or a small card room. Most casinos offer food and drinks, and many have shows or other entertainment. Some are famous for their architecture or location, such as the Bellagio in Las Vegas and the Casino de Monte-Carlo in Monaco. Others are known for their luxury or historicity, such as the Casino Baden-Baden in Germany. Most land-based casinos are heavily regulated by governments and have high security to prevent cheating or fraud.

Casinos earn billions of dollars each year from their gamblers. These profits are shared among the corporations, investors, and Native American tribes that own and operate them. The revenue is also a major source of taxation for state and local governments that legalize them.

Gambling has been part of human civilization for millennia, with evidence of dice throwing in 2300 BC and playing cards appearing around 500 AD. Modern-day casinos make extensive use of psychological and mathematical principles to encourage gambling. They provide their patrons with a virtual guarantee of net profit, and big bettors are often given extravagant inducements like free spectacular entertainment, limousine transportation, and luxury living quarters. Lesser bettors are offered complimentary food and drinks, free or reduced-fare transportation to the gambling floor, and discounted hotel rooms.

Gambling is most popular in the United States, where more than 1,000 casinos operate. The most successful are in Las Vegas, with New Jersey a close second and Chicago third. In the past, some states prohibited gaming establishments, but laws have been relaxed in recent decades. Many large cities now have casinos, including those that are located on Native American reservations.