The United States has 18 Ohio class submarines:

14 nuclear-powered SSBNs, each armed with 24 Trident II SLBMs; they are also known as "Trident" submarines, and provide the sea-based leg of the triad of the United States strategic deterrent forces

4 nuclear-powered SSGNs, each armed with 154 Tomahawk cruise missiles with conventional warheads

The 14 Trident II SSBNs together carry around fifty percent of the total U.S. strategic warhead inventory. The exact number varies in an unpredictable and highly classified manner, below a maximum set by various strategic arms limitation treaties. Although the missiles have no pre-set targets when the submarine goes on patrol, the platform, when required, is capable of rapid targeting using secure and constant at-sea communications links. The Ohio class is the largest type of submarine ever constructed for the U.S. Navy, and internationally are second only to the Russian Typhoon class submarine in mass and size.

The Ohio class submarines were specifically designed for extended deterrence patrols. Each submarine is complemented by two crews, Blue and Gold, with each crew operating on a 100-day interval. To decrease the time in port for crew turnover and replenishment, three large logistics hatches are fitted to provide large diameter resupply and repair openings. These hatches allow sailors to rapidly transfer supply pallets, equipment replacement modules and machinery components, significantly reducing the time required for replenishment and maintenance. The class design allows the vessel to operate for 15+ years between overhauls. The boats are purported to be as stealthy at 20 knots (their cruising speed) as previous boats were at a dead crawl of 6 knots, although exact information remains classified.

The first eight Ohio class submarines were originally equipped with 24 Trident I C-4 ballistic missiles. Beginning with the ninth Trident submarine, USS Tennessee, the remaining ships were equipped with the upgraded Trident II D-5 variant as they were constructed. The Trident II missile carries nine multiple inertial re-entry vehicles (MIRVs), in sum delivering more deterrence than the Trident I and with much greater accuracy. Starting with USS Alaska in 2000, the navy began converting the remaining C-4 equipped submarines to D-5 missiles; this was completed late in 2005.

The first eight boats were homeported in Bangor, Washington to replace the Polaris A-3 carrying submarines that were then being decommissioned. The remaining ten boats were originally homeported in Kings Bay, Georgia, replacing the Atlantic-based Poseidon and Trident Backfit submarines. During the conversion of the first four hulls to SSGNs (see below), five boats, Pennsylvania, Kentucky, Nebraska, Maine, and Louisiana, were shifted from Kings Bay to Bangor. Further shifts are occurring as the country's strategic needs change.

After the end of the cold war plans called for Ohio to be retired in 2002, followed by three of her sisters. However, Ohio, Michigan, Florida, and Georgia instead were slated for modification, to remain in service as conventional, guided missile submarines (SSGNs).

Beginning in 2002�2010, 22 of the 24 88-inch (2.2 m) diameter Trident missile tubes will be modified to contain large vertical launch systems (VLS), one configuration of which may be a cluster of seven Tomahawk missiles. In this configuration, the number of cruise missiles carried could be a maximum of 154, the equivalent of what is typically deployed in a surface battle group. Other payload possibilities include new generations of supersonic and hypersonic cruise missiles, unmanned air vehicles (UAVs), the ADM-160 Miniature Air-Launched Decoy, sensors for anti-submarine warfare or intelligence, surveillance and reconnaissance missions, counter-mine warfare payloads such as the AN/BLQ-11 Long Term Mine Reconnaissance System (LMRS), and the broaching universal buoyant launcher (BUBL) and stealthy affordable capsule system (SACS) specialized payload canisters.

The other two Trident tubes may be replaced by swimmer lockout and equipment pods. For special operations, a minisub can be mounted on the bow and the boat will be able to transport a sizeable number of special operations personnel, such as the Navy SEALs.

On September 26, 2002, the Navy awarded GD Electric Boat a $442.9 million contract to begin the first phase of the SSGN submarine conversion program. Those funds covered only the initial phase of conversion for the first two boats on the schedule. Advance procurement was funded at $355 million in fiscal year 2002, $825 million in the FY 2003 budget and, through the five-year defense budget plan, at $936 million in FY 2004, $505 million in FY 2005, and $170 million in FY 2006. Thus, the total cost to refit the four boats is just under $700 million per vessel.

In November 2002 Ohio entered drydock, beginning a 36-month refueling and conversion overhaul. Electric Boat announced on 9 January 2006 that the conversion had been completed. Ohio rejoined the fleet in 2006. She will be followed by Michigan, Florida, and Georgia. These four SSGNs are expected to remain in service until 2023-2026.