Casinopolis is the name of a casino located in Station Square.
Sonic the Hedgehog and Miles "Tails" Prower first visited the casino in their hunt to find Chaos Emeralds in order to prevent Doctor Eggman from powering Chaos. The casino was giving away one of the emeralds as a prize at the time. Although the duo succeeded in winning the Emerald, they immediately lost it when Eggman ambushed them at the casino entrance. Knuckles the Echidna also visited the casino around this time in his hunt for the shattered Master Emerald shards. (VD: SA/SADX)
When The Shattered World Crisis hit Station Square, many visitors became trapped inside when the event caused the whole city to flood. Soon, they where rescued and transferred to the rooftops during the Knothole Freedom Fighters evacuation efforts. (StH: #257)