In general, most states will require a patron to be at least 21 years old to be allowed on casino grounds. For example, in California, both 18-year-olds and 21-year-olds will be able to gamble as it will depend on the casino they enter. Bear in mind that the legal gambling age in the USA can vary depending on the state. The states which boast the highest number of legal casinos are Nevada, California, Mississippi, Oklahoma and Washington. Some of the best ones are the Aria Resort and Casino in Las Vegas (NV), the Bellagio in Las Vegas (NV), Atlantis Casino Resort Spa in Reno (NV), Foxwoods in Mashantucket (CT) and The Cosmopolitan of Las Vegas (NV). With time, there are certain brands that have evolved to be the most luxurious and popular casinos in the United States. There are over 460+ commercial land-based casinos available in the country. Nowadays, there are literally hundreds of casino establishments that US citizens can visit and enjoy. Over time more and more states decided to legalize casino gambling, and by the mid-’90s, nine more states had done so. In 1978, the first land-based casino that was legal outside of Nevada opened its doors in Atlantic City, New Jersey. Before the 1970’s legal casino gambling was available only in Las Vegas, Nevada. Guide to Legal US CasinosGambling has been a part of the US’s history for a long time.