The "Pennsylvania"-class design continued the all-or-nothing principle of armoring only the most important areas of the ship begun in the "Nevada" class. The waterline armor belt of Krupp armor measured thick and covered only the ship's machinery spaces and magazines. It had a total height of , of which was below the waterline; beginning below the waterline, the belt tapered to its minimum thickness of . The transverse bulkheads at each end of the ship ranged from 13 to 8 inches in thickness. The faces of the gun turrets were thick while the sides were thick and the turret roofs were protected by of armor. The armor of the barbettes was thick. The conning tower was protected by of armor and had a roof eight inches thick.