SS City of Tokio (sometimes spelled City of Tokyo) was an iron steamship built in 1874 by Delaware River Iron Ship Building and Engine Works for the Pacific Mail Steamship Company. City of Tokio and her sister ship City of Peking were at the time of construction the largest vessels ever built in the United States, and the second largest in the world behind the British leviathan Great Eastern. City of Tokio holds the distinction of being the first ship to bring members of the Issei, or first-generation Japanese migrants, to the United States.