USS Pennsylvania, name-ship of a class of six 13,680 ton armored cruisers, was built at Philadelphia, Pennsylvania. Commissioned in March 1905, she operated off the U.S. Atlantic Coast and in the Caribbean until September 1906, when she departed for service in Far Eastern waters. A year later, Pennsylvania arrived in California to begin a decade of duty along the Pacific coasts of North and South America. A cruise to Peru and Chile in 1910 was followed by temporary aviation service early in 1911. On 18 January of that year, after she had been fitted with a wooden landing platform aft, civilian aviator Eugene Ely landed his Curtiss biplane on board, the first time an airplane had set down on a warship's deck.

Pennsylvania was in reserve at the Puget Sound Navy Yard between mid-1911 and mid-1913, during which time she was fitted with a "cage" foremast. She was renamed Pittsburgh in August 1912, in order to make the name Pennsylvania available for the planned Battleship # 38. The cruiser operated off the Mexican west coast during the mid-"Teens", a time of great instability in that nation. In 1917-1918, after the United States entered World War I, she was flagship of a squadron of armored cruisers that patrolled off South America in both the Pacific and the Atlantic. Several months after the end of the conflict, in June 1919, Pittsburgh began a two-year deployment to European waters. When the Navy implemented its hull number system in mid-1920, she was designated CA-4. Between 1922 and 1926 Pittsburgh was again in the eastern Atlantic and the Mediterranean as flagship of Commander, U.S. Naval Forces in Europe.

After an overhaul in mid-1926, which included removing some of her boilers and her forward smokestack, Pittsburgh steamed to the Far East to become flagship of the Asiatic Fleet. Her activities in that region included putting armed landing parties ashore during the 1927 civil war in China and paying visits to ports in Southeast Asia and the Dutch East Indies. USS Pittsburgh left the Western Pacific in April 1931, arriving back on the U.S. East Coast in late June. Decommissioned in July, she was used in weapons tests later in the year and sold for scrapping in late December 1931.