It was an abrupt end to an operation that began in when the Argosy opened on Sioux City's riverfront to great fanfare. It was owned by Penn National Gaming. Landmark & Historical Place. The former Argosy Sioux City casino has been sold to an Illinois firm that hopes to move the riverboat down the Missouri River as early as next. Sioux City, IA () Also at this address. Argosy Casino. Previously, the. Argosy Casino Sioux City Website ; Casino. Court St. It was a riverboat casino that has been closed for quite a while. Argosy Casino, Sioux City, IA. Don't plan a trip to Sioux City with the idea you will gamble at the Argosy. +1 () ; Website. 28 likes · were here. You can't even. Argosy Casino Sioux City was a riverboat casino located on the Missouri River in Sioux City, Iowa. Directions. Larsen Park Rd Sioux City IA USA ; Telephone. . Reviews from Argosy Casino employees about Argosy Casino culture, salaries, benefits, work-life balance, management, job security, and more. Advertisement. The former Argosy riverboat casino has pulled away from its dock in Sioux City and started its journey to a shipyard in Illinois. Argosy Casino Sioux City ; Address. () More.