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)
After Renfield T. Rodent was released from prison by Dr. Eggman during his takeover of Angel Island, he opened the casino as a front by Eggman in order to replace the patrons with Auto Automatons after scanning their minds with the slot machines. The Chaotix put an end to the scheme after being sent by the Kingdom of Acorn to investigate, however, the casino was subsiquentally stripped of the mind-reading equipment once Rodent was re-arrested. (StH: #166)