USS Supply, ex-Illinois, was a schooner-rigged iron steamer built in 1873 by William Cramp & Sons of Philadelphia. Illinois was purchased by the Navy Department from the International Navigation Company on 30 April 1898 for $325,000.00 and commissioned as Supply, Lt. Comdr. R. R. Ingersoll in command.

SS Illinois was an iron passenger-cargo steamship built by William Cramp & Sons in 1873. The last of a series of four Pennsylvania-class vessels, Illinois and her three sister ships—Pennsylvania, Ohio and Indiana—were the largest iron ships ever built in the United States at the time of their construction, and amongst the first to be fitted with compound steam engines. They were also the first ships to challenge British dominance of the transatlantic trade since the American Civil War.