Intercontinental ballistic missiles or ICBM's are long-range missiles using a ballistic trajectory involving a significant ascent and descent including suborbital and partial orbital trajectories. An ICBM differs little technically from other ballistic missiles, the IRBM, SRBM or the newly named theatre ballistic missile; all are defined in terms of maximum range.
Modern ICBMs typically carry multiple independently targetable reentry vehicles (MIRVs), each of which carries a nuclear warhead, allowing a single missile to hit multiple targets. MIRV was an outgrowth of the rapidly shrinking size and weight of modern warheads. It has also proved to be an "easy answer" to the deployment of ABM systems – it is far less expensive to add more warheads to an existing missile system than to build an ABM system capable of shooting down the additional warheads.
The low flying, guided cruise missile is an alternative to ballistic missiles.
Specific types of US ballistic missiles include: