Serving in the western Atlantic in 1916-18, these ships visited Europe just after the November 1918 Armistice and were thereafter stalwart members of the Navy's Battle Fleet. Reconstructed in 1929-31, they received greater main battery gun elevation, tripod masts to support improved gun directors and modern aircraft catapults. The ships' secondary gun batteries were updated, as was protection against gunfire, aircraft bombs and torpedoes. Pennsylvania, assigned to duty as a fleet flagship, was given a greatly enlarged armored conning tower. Now capable of long-range gunfire in an age when the role of aircraft was steadily growing, the ships spent another decade in the Nation's battle line.
The Pennsylvanias were both present during Japan's December 7, 1941 attack on Pearl Harbor. Arizona blew up in action, the most dramatic and costly casualty of the raid. Pennsylvania was only lightly damaged, and she served in the Pacific throughout World War II. Fitted with a new secondary battery of twin-mounted 5"/38 guns in late 1942, she supported many amphibious invasions and was present during the world's last battle between big-gun warships, the Battle of Surigao Strait on October 25, 1944. A torpedo hit in August 1945 proved that her watertight integrity, like that of other old warships, could not be relied upon. With other obsolete battleships, Pennsylvania was an atomic bomb target in 1946 and was scuttled at sea two years later.
The Pennsylvania class included two ships, both built on the east coast: