The hull, first two decks, and steam engines were ordered in 1924 from the William Denny & Brothers shipyard on the River Leven adjoining the River Clyde at Dumbarton, Scotland. "Delta Queen" and her sister, "Delta King", were shipped in pieces to Stockton, California in 1926. There the California Transportation Company assembled the two vessels for their regular Sacramento River service between San Francisco and Sacramento, and excursions to Stockton, on the San Joaquin River. At the time, they were the most lavishly appointed and expensive sternwheel passenger boats ever commissioned. Driven out of service by a new highway linking Sacramento with San Francisco in 1940, the two vessels were laid up and then purchased by Isbrandtsen Steamship Lines for service out of New Orleans. During World War II, they were requisitioned by the United States Navy for duty in San Francisco Bay as USS "Delta Queen" (YHB-7/YFB-56). During the war, the vessels were painted battleship gray and used in transporting wounded from ocean-going ships in San Francisco Bay to area hospitals.