The Diamond Jo Casino is a gambling casino and entertainment complex located in the Port of Dubuque, in Dubuque, Iowa. The casino is owned and operated by Dubuque-based Peninsula Gaming, which also operates the Diamond Jo Casino - Worth in Northwood, Iowa. It is a member of the Iowa Gaming Association, and its license is held by the Dubuque Racing Association, which operates the Dubuque Greyhound Park & Casino. Beginning operations on May 18, 1994, the Diamond Jo was a 3-level, 305-foot (93 m), 1,500-passenger vessel in Dubuque's Ice Harbor. The boat was a dockside that did not cruise, the casino became land-based when its new facility opened December 11, 2008.