USS Pennsylvania (ACR-4) formed the lead ship of the six-strong Pennsylvania-class of armored cruisers in service with the United States Navy during the early 1900s. Her sisters included USS West Virginia (ACR-5), USS California (ACR-6), USS Colorado (ACR-7), USS Maryland (ACR-8) and USS South Dakota (ACR-9). The class was constructed from 1901 until 1908 and served until 1927 before being scrapped to fulfill the American commitment to the London Naval Treaty of 1930. Of the six completed, one was lost. All were renamed at different times in their ocean-going careers to free up designations for incoming battleships joining the service.
USS Pennsylvania was ordered on March 3rd, 1899 and built by William Cramp & Sons of Philadelphia, Pennsylvania, her keel being laid down on August 7th, 1901. She was launched on August 22nd, 1903 and formally commissioned on March 9th, 1905.
As completed, USS Pennsylvania featured a displacement of 13,900 tons and a length of 504 feet, a beam of 69.6 feet and a draught of 24 feet. Power was from 32 x Niclausse boilers feeding 2 x triple expansion reciprocating engines driving 23,000 horsepower to 2 x shafts. Speeds in ideal conditions could reach up to 22 knots. Her crew complement numbered 889 led by 80 officers and included some 64 marine elements. The ship's primary battery was 4 x 8" (200mm) /40 caliber Mark 5 main guns set as two guns to two turrets. This was supported by 14 x 6" (150mm) /50 caliber Mark 6 guns and 18 x 3" (76mm) /50 caliber fast-firing cannons. 12 x 3-pounder (47mm) Driggs-Schroeder guns were also carried for shorter-ranged work and 2 x 1-pounder (37mm) Driggs-Schroeder guns were used for salute functions. As was the case with other warships of the period, Pennsylvania was also completed with torpedo tubes, these being 2 x 18" (460mm) launchers. Armor protection ranged from 6" at the belt and 6" on her deck to 6.5" at the turrets and 9 inches at the conning tower.
Her profile included four smoke funnels at midships bookended by two main masts. Her bridge section was appropriately held well-forward in the design with a commanding view over the forecastle. A primary turret was fitted fore and the other aft while smaller-caliber guns protruded from her upper hull sides.
Her first actions involved cruising the American east coast and Caribbean waters. In late 1906 she was sent to Asia to enforce American trade routes and interests overseas concerning the Pacific. The vessel then operated along the American west coast for the latter half of 1907 and managed calls at Chile and Peru during 1910. Prior o 1911, she underwent a refit which changed her propulsion scheme to include 8 x modified boilers with 12 x Babcock & Wilcox boiler units. Her added two more saluting guns and lost her 12 x 3-pounders. USS Pennsylvania then became the recipient of the first fixed-wing aircraft landing on a ship (with arrestor hook) when the event was recorded on January 18th, 1911. To accommodate the task, a short flight deck was added over her stern section. The event took place at San Francisco Bay, California with Eugene Ely at the controls of a pusher-powered biplane.
She was sent to reserve in mid-1911 and used as a trainer for a time. Because of the influx of new American battleships, she lost the name "Pennsylvania" and was recommissioned as "USS Pittsburgh" on August 27th, 1912, ending her days under this name - though reclassified on July 17th, 1920 under the hull symbol of (CA-4). Prior to 1921, she was part of another refit.
As Pittsburgh she continued her ocean-going career before being sold off for scrap on December 21st, 1931.