USS St. Louis, a transatlantic passenger liner built by the William Cramp & Sons Building & Engine Company, Philadelphia, Pa., was launched on 12 November 1894; sponsored by Mrs. Grover Cleveland, wife of the President of the United States; and entered merchant service in 1895, under United States registry for the International Navigation Co., of New York with her maiden voyage between New York and Southampton, England.

USS St. Louis (CL-49), the lead ship of her class of light cruiser, was the fifth ship of the United States Navy named after the city of St. Louis, Missouri.

USS St. Louis has been the name of six ships in the United States Navy. All were named for the city in Missouri.

The fourth USS St. Louis, Cruiser No. 20 (C-20), was the lead ship of her class of cruisers in the United States Navy.

USS St. Louis (AKA-116/LKA-116), a Charleston class amphibious cargo ship, is the sixth U.S. ship to bear the name. She served as a commissioned ship for 22 years and 11 months.

USS St. Louis was a sloop in the United States Navy through most of the 1800s.