* Land-based intercontinental ballistic missiles, or ICBMs;
* Sea-based, nuclear submarine-launched ballistic missiles, or SLBMs; and
* Air-based nuclear weapons of the U.S. Air Force’s heavy bomber group
* As of 1999, the U.S. was said to have 12,000 nuclear weapons of all types stockpiled
* In its Strategic Arms Reduction Treaty (START) declaration for 2003, the U.S. listed 5968 deployed warheads as defined by START rules.
* For 2007, the Bulletin of the Atomic Scientists listed the U.S. with about 5,400 total nuclear warheads: around 3,575 strategic and 500 nonstrategic warheads; and about 1,260 additional warheads held in the inactive stockpile. Other warheads are in some step of the disassembly process.
* The exact number as of Sept. 30, 2009, was 5,113 warheads, according to a U.S. fact sheet released May,3 2010.