The Diamond Jo Riverboat Casino is owned and operated by Peninsula Gaming, LLC. The Diamond Jo Casino began operation in 1994 under ownership of the Greater Dubuque Riverboat Entertainment Company, L.C.. In October 1995, GDREC replaced the vessel with a larger boat. The latest Diamond Jo is a three-story, approximately 51,900 square foot riverboat casino, replicating a classic 19th century paddlewheel. The riverboat has the capacity for 1,390 patrons, features a spacious two-story atrium, and offers 777 slot machines and 17 table games in approximately 17,800 square feet of gaming space. Peninsula spent nearly $1 million updating the casino area after the company purchased the Casino on July 15, 1999.

Adjacent to the Diamond Jo is a two-story, approximately 33,000 square foot dockside pavilion, featuring the Lighthouse Grill restaurant, and HighSteaks Restaurant. The Diamond Jo is open seven days a week and functions as a dockside riverboat with continuous boarding.

The Diamond Jo Casino is a member of the Iowa Gaming Association.

Number of Tables: 17

Number of Slots, Video Poker and Keno: 777