To find the best gambling properties, whether this is a casino, a racetrack, or a sportsbook, we first have decided to see what states allow gambling for 18-year-olds and under what circumstances. Today, we take a look at the gambling venues that accept 18-year-olds in the United States. With a mesh of regulation and state laws, it may often be not immediately clear what gambling options are available to you without doing a bit of due diligence beforehand. The United States has a long tradition of gambling.