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