Naval Systems

Ohio-class guided-missile submarine

Also known as
  • Ohio SSGN
  • Ohio-class SSGN
  • Ohio-class cruise missile submarine
  • Trident SSGN
  • SSGN 726 class

The Ohio-class guided-missile submarine is the U.S. Navy's converted SSGN platform for large Tomahawk strike loads, clandestine command-and-control, and special-operations support. Four former Ohio ballistic-missile submarines were refueled and converted in the 2000s, giving each boat up to 154 Tomahawk land-attack missiles plus space for SOF teams and equipment. The class has documented strike use in Libya in 2011 and in the 2020 United States-Iran Conflict during Operation Midnight Hammer.

Ohio-class guided-missile submarine, Guided-missile submarine, Naval Systems
Image source: USS Ohio (SSGN 726).jpg

Role in Conflicts

2011 First Libyan Civil War
Role in conflict
Submarine-launched Tomahawk strike platform

USS Florida (SSGN 728) fired Tomahawk missiles during Operation Odyssey Dawn in March 2011, including the first combat strike employment of the converted Ohio SSGN platform.

2020 United States-Iran Conflict
Role in conflict
Submarine-launched Tomahawk strike platform

A U.S. Ohio-class guided-missile submarine launched more than two dozen Tomahawk land-attack missiles toward Isfahan during Operation Midnight Hammer.

Profile / Specs

Profile

Origin
United States
Type
Guided-missile submarine
Service note
2000s-present
Designer
General Dynamics Electric Boat Division
Designed
Ohio-class SSBN conversion program began in the 2000s
Number built
4 converted SSGNs

Specifications

Length
560 ft (170.69 m)
Beam
42 ft (12.8 m)
Displacement
16,764 tons surfaced; 18,750 tons submerged
Speed
20+ knots
Crew
Two alternating crews of 15 officers and 144 enlisted
Armament
Up to 154 Tomahawk missiles, Mk48 torpedoes, and 4 torpedo tubes
Payload arrangement
Up to 22 missile tubes fitted with seven-shot Multiple-All-Up-Round Canisters
Special-operations capacity
Up to 66 SOF personnel; two forward missile tubes converted to lock-out chambers
Communications fit
Common Submarine Radio Room and two High-Data-Rate antennas
Propulsion
One nuclear reactor, one shaft
Conversion Role

The SSGN conversion kept four early Ohio-class hulls in service after strategic-force reductions, replacing the ballistic-missile mission with conventional land attack, SOF support, and improved communications. The result was a small force of nuclear-powered submarines with unusually dense vertical-launch capacity and the endurance to remain forward deployed.

Conversion areaOperational effectDocumented detail
Strike payloadLarge conventional salvo capacityUp to 22 missile tubes can carry seven-shot Tomahawk canisters, giving each boat a maximum load of 154 Tomahawks.
SOF supportClandestine insertion and supportThe two forward missile tubes were converted to lock-out chambers and the boats can host up to 66 SOF personnel.
Command roleForward deployed control nodeCommon Submarine Radio Room and High-Data-Rate antennas were added during conversion for improved communications.
Variants

The SSGN force consists of four converted Ohio-class ballistic-missile submarines, each redesignated as a guided-missile submarine after refueling and conversion work in the 2000s.

VariantConfigurationDesignation notes
USS Ohio (SSGN 726)Lead converted SSGN

Entered conversion in November 2002, completed conversion in December 2005, and made its first SSGN deployment in October 2007.

Sources: Guided Missile Submarines - SSGN

USS Michigan (SSGN 727)Pacific-based converted SSGN

Started shipyard availability in October 2004 and was delivered as a converted SSGN in November 2006.

Sources: Guided Missile Submarines - SSGN

USS Florida (SSGN 728)Atlantic-based converted SSGN

Returned to the fleet in April 2006 and later fired Tomahawks during Operation Odyssey Dawn in Libya.

Sources: Guided Missile Submarines - SSGN, A Promise Kept

USS Georgia (SSGN 729)Atlantic-based converted SSGN

Completed conversion in December 2007, the last of the four Ohio SSGN conversions.

Sources: Guided Missile Submarines - SSGN

Carried Munitions

The SSGN conversion shifted four Ohio-class boats from strategic ballistic-missile patrols to conventional strike and submarine self-defense loads.

Carried itemItem typeCarriage evidence
BGM-109 Tomahawk Land Attack Missile, Ship- and submarine-launched land-attack cruise missile, MunitionsBGM-109 Tomahawk Land Attack MissileSubmarine-launched land-attack cruise missile

Each converted Ohio SSGN can carry up to 154 Tomahawk land-attack missiles in seven-shot canisters fitted inside up to 22 missile tubes.

Sources: Guided Missile Submarines - SSGN

Mark 48 heavyweight torpedo, Submarine-launched heavyweight torpedo, Naval SystemsMark 48 heavyweight torpedoHeavyweight torpedo

The U.S. Navy fact file lists Mk48 torpedoes and four torpedo tubes as part of the Ohio SSGN armament fit.

Sources: Guided Missile Submarines - SSGN

Timeline

Ohio-class guided-missile submarine Key Events

  1. USS Florida fires in Libya

    USS Florida joined Operation Odyssey Dawn strikes against Libyan targets and later completed the campaign with 93 Tomahawk launches.

    Sources: A Promise Kept

  2. Ohio SSGN used in Operation Midnight Hammer

    A U.S. Ohio-class guided-missile submarine launched Tomahawk missiles toward Iran during Operation Midnight Hammer.

    Sources: Here's the role an Ohio-class submarine played in the strikes on Iran

Media

Ohio-class guided-missile submarine Videos

Ohio-class guided-missile submarine Images

Ohio-class guided-missile submarine, Guided-missile submarine, Naval Systems - view 1
Source: US Navy 100928-N-9204B-001 USS Michigan at Yokosuka.jpg
Ohio-class guided-missile submarine, Guided-missile submarine, Naval Systems - view 2
Source: The Ohio-class guided-missile submarine USS Florida (SSGN 728) (5841091).jpg
Ohio-class guided-missile submarine, Guided-missile submarine, Naval Systems - view 3
Source: US Navy 090822-N-2911P-005 USS Georgia submerging.jpg
Related Weapon Systems
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Sources

Guided Missile Submarines - SSGNPublisher: U.S. Navy | Note: Supports Ohio-class SSGN background, builder, conversion history, ship list, communications fit, special-operations features, and general characteristics including displacement, crew, speed, and armament. | Accessed: 2026-06-29A Promise KeptPublisher: U.S. Naval Institute Proceedings | Note: Supports the 2011 First Libyan Civil War: used by USS Florida as a converted Ohio-class guided-missile submarine that launched Tomahawk missiles during Operation Odyssey Dawn. | Accessed: 2026-06-29USS Florida Arrives at Naval Submarine Base Kings BayPublisher: DVIDS / U.S. Navy | Note: Supports the 2011 First Libyan Civil War: used by USS Florida when the Ohio-class guided-missile submarine participated in Operation Odyssey Dawn and launched Tomahawk land attack missiles. | Accessed: 2026-06-29Operation Midnight Hammer press conference transcriptPublisher: U.S. Department of War | Note: Supports the 2020 United States-Iran Conflict: used by a U.S. submarine when it launched more than two dozen Tomahawk land attack cruise missiles at Isfahan during Operation Midnight Hammer. | Accessed: 2026-06-29Here's the role an Ohio-class submarine played in the strikes on IranPublisher: Defense News | Note: Supports the 2020 United States-Iran Conflict: fielded by the United States as an Ohio-class guided-missile submarine that launched Tomahawk land-attack cruise missiles into Iran during Operation Midnight Hammer. | Accessed: 2026-06-29USS Ohio (SSGN 726).jpgPublisher: Wikimedia Commons | Note: Supports the primary image provenance and public-domain status for the Ohio-class guided-missile submarine image. | Accessed: 2026-06-29US Navy 100928-N-9204B-001 USS Michigan at Yokosuka.jpgPublisher: Wikimedia Commons | Note: Supports gallery image provenance and public-domain status for the USS Michigan Ohio-class guided-missile submarine image. | Accessed: 2026-06-29The Ohio-class guided-missile submarine USS Florida (SSGN 728) (5841091).jpgPublisher: Wikimedia Commons | Note: Supports gallery image provenance and public-domain status for the USS Florida Ohio-class guided-missile submarine image. | Accessed: 2026-06-29US Navy 090822-N-2911P-005 USS Georgia submerging.jpgPublisher: Wikimedia Commons | Note: Supports gallery image provenance and public-domain status for the USS Georgia Ohio-class guided-missile submarine image. | Accessed: 2026-06-29