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