The legal age to gamble at a casino varies by location, typically ranging from 18 to 21 years old. In the United States, most states require individuals to be at least 21 to participate in casino games, while some allow 18-year-olds to play certain games like poker or slots. It's essential to check the specific regulations of the state or country you are in, as they can differ significantly. Always ensure you have valid identification to verify your age when visiting a casino.