USS United States was a wooden-hulled, three-masted heavy frigate of the United States Navy and the first of the six original frigates authorized for construction by the Naval Act of 1794. Joshua Humphreys designed the frigates to be the young Navy's capital ships, and so United States and her sisters were larger and more heavily armed and built than standard frigates of the period. She was built at Humphrey's shipyard in Philadelphia, Pennsylvania and launched on 10 May 1797 and immediately began duties with the newly formed United States Navy protecting American merchant shipping during the Quasi-War with France.