The LGM-30 Minuteman is a U.S. land-based intercontinental ballistic missile (ICBM), in service with the Air Force Global Strike Command. As of 2016, the LGM-30G Minuteman III version[a] is the only land-based ICBM in service in the United States.
Peaking at 1,000 missiles in the 1970s, the current U.S. force consists of 450 Minuteman-III missiles in missile silos around Malmstrom AFB, Montana; Minot AFB, North Dakota; and F.E. Warren AFB, Wyoming. By February 2018 this will be reduced to 400 armed missiles, with 50 unarmed missiles in reserve, and four non-deployed test launchers to comply with the New START treaty. The Air Force plans to keep the missile in service until at least 2030. It is one component of the U.S. nuclear triad—the other two parts of the triad being the Trident submarine-launched ballistic missile (SLBM), and nuclear weapons carried by long-range strategic bombers.
Source: LGM-30 Minuteman – Wikipedia