 The ship was armed with a main battery of four 12 inch / 40 Mark 4 guns in two twin gun turrets on the centerline, one forward and aft. The secondary battery consisted of eight 8-inch (203 mm) / 45 guns and twelve 6-inch (152 mm) / 45 guns. The 8-inch guns were mounted in four twin turrets; two of these were superposed atop the main battery turrets, with the other two turrets abreast the forward funnel. The 6-inch guns were placed in casemates in the hull. For close-range defense against torpedo boats, she carried twelve 3-inch / 50 guns mounted in casemates along the side of the hull and twelve 3-pounder guns. She also carried two 1-pounder guns. As was standard for capital ships of the period, New Jersey carried four 21 in (530 mm) torpedo tubes, submerged in her hull on the broadside.
