Soviet Union's Missles

I just thought about this today- all of Russia's nuclear missles are inherited from the Soviet Union. Does this mean the Soviets ONLY build nuke Silos in Russia fearing that the union would break up one day? Or did they just transfer nukes into Russia when the union collapsed? Why else would Russia be the only former-SSR with nukes?

They transferred them in some cases. In others, the countries destroyed them. Ukraine is a good example. Overall, nuclear weapons and missiles populated large portions of the USSR, not just Russia. Under Post-Soviet Era, you can find a list of countries that had Soviet nuclear weapons.