Gambling establishments that offer a variety of games of chance. Some casinos also feature restaurants, free drinks and stage shows. Casinos may be located in Las Vegas, Atlantic City or other cities around the world. Some casinos specialize in certain types of gambling, such as poker or sports betting.

Most games of chance have mathematically determined odds that give the house an advantage over players, known as the house edge. The house edge is the net result of the percentage of bets made by customers that lose and the number of bets placed. This difference between expected value and actual payout is the source of casino profits, after paying out winning bets and taking in vig (vigorish) or rake (in games such as poker where players compete against each other). Casinos also earn money from complimentary goods and services, known as comps. These can include free hotel rooms, meals, tickets to shows and even airline and limo service for high rollers.

Casinos are subject to many security measures to prevent cheating and stealing by patrons. Tables, windows and doorways are constantly watched by cameras. A separate room filled with banks of security monitors lets staff quickly adjust surveillance to focus on suspicious patrons. Some casinos also employ pit bosses, who monitor games and ensure that rules are being followed.

Although gambling likely existed in some form before recorded history, the modern casino is the result of a series of innovations. The earliest casino was probably a saloon in the American Wild West, but the industry developed rapidly in Nevada during the 1950s as mobsters sought to take advantage of legalized gambling. The mobsters brought money to fund the venture and became personally involved, buying up gaming tables and influencing the outcome of some games.