A casino is a building or large room used for gambling. Casinos are most commonly built near or combined with hotels, restaurants, retail shops, and other tourist attractions. Some casinos are operated by governments, while others are private enterprises. Many states have legalized casinos to encourage tourism and commerce. Others ban them outright. The United States has the most casinos, with over 1,000, followed by Canada, with over 40, and then Italy with 19. The number of casinos is increasing rapidly. When New Jersey permitted them in the 1970s, a groundswell of change took hold throughout the nation. Many American Indian tribes also operate casinos. Casinos may be located in or around cities and towns, on tribal lands, on cruise ships, or in independent facilities such as those in Las Vegas.
In a casino, customers gamble by playing games of chance or skill. Most games have mathematically determined odds that give the house an advantage over the patrons. This advantage is known as the house edge, and it can be calculated in advance by mathematicians who specialize in gaming analysis. Casinos use these calculations to maximize profits and limit losses.
Because casino patrons can be tempted to cheat or steal, security measures are paramount in most casinos. Patrons are monitored by video cameras and surveillance personnel. Staff are trained to spot deception. Casinos often have catwalks in the ceiling that allow surveillance personnel to look directly down on table and slot games, through one-way glass. Casinos also use electronic systems to monitor betting chips, so they can oversee the exact amounts bet minute-by-minute; roulette wheels are electronically supervised to discover any abnormal deviation from their expected results.