A casino is a gambling establishment offering an array of games of chance and in some cases skill. While a large percentage of players lose money, those who win can be very wealthy in the short term. The odds on most casino games are mathematically determined to provide a long-term advantage for the house, or in terms of expected value more precisely called the house edge. In some cases, such as blackjack and baccarat, the house edge is so low that it is not profitable for anyone to play at all. In games where players compete against each other, such as poker, the house earns a commission, or rake, that is often a significant percentage of the total pot.

A casino may be located in a land-based building or on an ocean liner or cruise ship. In the United States, casinos are most frequently found in Las Vegas and Atlantic City, but they also exist in Reno, Colorado, New Jersey, and Puerto Rico. In the 1980s casinos began appearing on American Indian reservations, which are exempt from state anti-gambling laws. Online casinos allow players to gamble from the comfort of their homes, without having to travel to a physical casino. These sites usually have a wide selection of casino games and reliable software providers. They may offer a variety of payment methods and fast payout times. In addition, they should have customer support that is available around the clock.