41 for Freedom refers to the US Navy Fleet Ballistic Missile (FBM) submarines from the George Washington, Ethan Allen, Lafayette, James Madison, and Benjamin Franklin classes. All of these submarines were commissioned 1959–1967, as the goal was to create a credible, survivable sea-based deterrent as quickly as possible. These submarines were nicknamed "41 for Freedom" once the goal of 41 nuclear-powered ballistic missile submarines (SSBNs) was established in the early 1960s. The 1972 SALT I Treaty limited the number of American submarine-launched ballistic missile tubes to 656, based on the total missile tubes of the forty-one submarines, in line with the treaty's goal of limiting strategic nuclear weapons to the number already existing.

A submarine-launched ballistic missile (SLBM) is a ballistic missile capable of being launched from submarines. Modern variants usually deliver multiple independently targetable reentry vehicles (MIRVs), each of which carries a nuclear warhead and allows a single launched missile to strike several targets. Submarine-launched ballistic missiles operate in a different way from submarine-launched cruise missiles.