USS PhiladelphiaSix ships of the United States Navy have been named USS Philadelphia, after the city of Philadelphia, Pennsylvania.
- The first Philadelphia was a gondola built in 1776 on Lake Champlain by Benedict Arnold and sunk in the Battle of Valcour Island.
- The second Philadelphia was a 28-gun sailing frigate active in the Quasi-War, captured in the First Barbary War and later burned.
- The third Philadelphia was a side-wheel steamer used in the American Civil War.
- The fourth Philadelphia (C-4) was a protected cruiser commissioned in 1890 and in service until 1926.
- The fifth Philadelphia (CL-41) was a light cruiser commissioned 1937, active in World War II, and sold to Brazil in 1951.
- The sixth Philadelphia (SSN-690) is a Los Angeles-class attack submarine commissioned in 1977 and on active service as of 2003.