Naval History and Heritage Command

Commissioned between 1981 and 1997, 18 Ohio-class nuclear-powered ballistic missile submarines (SSBNs) replaced the original 41 for Freedom SSBNs and became the largest submarines built by the U.S. Navy. In the 2000s, the Navy converted the first four Ohio-class SSBNs to guided missile submarines (SSGNs) after the 1994 Nuclear Posture Review recommended the U.S. only needed 14 SSBNs to meet strategic deterrence needs. In addition, the Department of Defense has permanently reduced the Ohio-class submarines’ submarine-launched ballistic missile (SLBM) capacity from 24 SLBMs to 20 in compliance with U.S.-Russia strategic nuclear arms control limits established by the New Strategic Arms Reduction Treaty.