The casino is located in Thackerville, Oklahoma and is open to the public. The largest casino in the world is Winstar. Regardless of when they were built, though, all of the casinos on our list have one thing in common: they're huge! #1 Winstar, Oklahoma, USA - World's Largest Casino in 2023 Some of these casinos are older, while others were built more recently. There are a number of casinos around the world that boast large gambling floors and expansive gaming areas.