Russia, of course.
From 1945 until the late 1970s or early 1980s the United States always had the most nuclear weapons. After then the USSR/Russia has had the most nuclear weapons.
America has the most nuclear weapons
Russia
As the category for this question is "Nuclear weapons", I'm presuming it refers to nuclear arms.As of 2012, the three countries with the largest stockpiles of nuclear weapons are, in order from most to least:RussiaUnited StatesFrance
In the most basic sense, proliferation of nuclear weapons is the spread of nuclear weapons and weapons usable technology in the world. In a much broader sense, it refers to the acquiring of capability to produce nuclear weapons, or weapons-grade nuclear material (high-enriched uranium, plutonium) by states previously not possessing them.
The most powerful.
nuclear weapons
RussiaUS
Nuclear fuel for nuclear power reactors Nuclear weapons
The country with the biggest stock of nuclear weapons, and hence, the biggest productor is the Russian Federation. They have over 12,000 nuclear warheads.
According to my research the most weapons country is the United States currently owns 9,600 nuclear weapons, while Russia currently owns 16,800. But Russia actually always had more nuclear weapons than the United States.