There Is Only One Factory In The United States Devoted To The Production Of?
Answer: Nuclear Missiles
Despite the fact that the United States has the largest nuclear arsenal in the world, all the assembly and disassembly of its nuclear weapons occurs in only one location: the Pantex Plant located in Carson County, Texas.
Originally constructed to manufacture conventional bombs during World War II, the plant was completely dormant after the end of the war until 1951, when the Department of Energy (then the Atomic Energy Commission) reactivated the plant to assemble nuclear missiles.
Although there are other factories involved in the production of nuclear weapons (there were four facilities in the Ohio/Kentucky/Tennessee region devoted to the refinement of Uranium-235), the Pantex Plant remains the only facility that handles the actual process of assembling the devices into fully functional weapons.
Image courtesy of the US Department of Energy.