The USS Queen of the West was a sidewheel steamer ram ship and the flagship of the United States Ram Fleet and the Mississippi Marine Brigade. It was built at Cincinnati, Ohio in 1854. It served as a commercial steamer until purchased by Colonel Charles Ellet Jr. in 1862 and converted for use as a ram ship. The ship operated in conjunction with the Mississippi River Squadron during the Union brown-water navy battle against the Confederate River Defense Fleet for control of the Mississippi River and its tributaries during the American Civil War.