A casino, also known as a gaming house or a gambling establishment, is an establishment where certain types of gambling take place. Casinos are often built near or combined with hotels, restaurants, retail shops, and other tourist attractions. In the United States, casinos are most commonly found in Atlantic City, New Jersey; Las Vegas; and Chicago. Some casinos are also located on Native American reservations.

Like other businesses in a capitalist society, casinos are in business to make money. They rake in billions of dollars each year for the companies, investors, and owners who run them, and they give back some of that income to their local communities through tax revenues.

Something about casinos, perhaps the presence of large amounts of cash or the high stakes involved, encourages people to cheat and steal. Casinos spend a great deal of time and money on security measures. Elaborate surveillance systems have cameras that can watch every table, stairway, and window at once, and the video feeds can be adjusted to focus on suspicious patrons by security personnel in a room filled with banks of monitors.

In addition to security measures, casinos try to create stimulating environments for their customers. They provide perks designed to encourage gamblers to spend more, such as free meals, drinks, hotel rooms, and show tickets. These incentives are called comps and have been a key source of revenue for many casinos in the past. However, in recent years, the number of people visiting casinos has dropped, and some analysts blame rising debt levels, declining incomes, and the rise of online gambling for this trend.