What is the difference between Russia, the Soviet Union and U.S.S.R?

The U.S.S.R. included:
Armenia
Azerbaijan
Belarus
Estonia (Granted independence in September 1991 and is not a member of the CIS)
Georgia (Withdrew from the CIS in May 2005)
Kazakhstan
Kyrgyzstan
Latvia (Granted independence in September 1991 and is not a member of the CIS)
Lithuania (Granted independence in September 1991 and is not a member of the CIS)
Moldova (Formerly known as Moldavia)
Russia
Tajikistan
Turkmenistan (Associate member of the CIS)
Ukraine (Participating member of the CIS)
Uzbekistan

The Soviet Union and the U.S.S.R. are the same thing.

The Soviet Union was the common name for the Union of Soviet Socialist Republics (U.S.S.R.)

The USSR was a confederation of multiple national republics; in practice its government and economy were highly centralized until its final years. The USSR replaced the Russian Empire.

Russia was the largest portion of the Russian Empire. After the fall of the USSR, Russia became defined to its pre empire boundaries.

When Russia allied with the Western Powers during WWII, and the combined Allies pushed the Germans back and defeated them, Russia did not relinquish control (at the end of the war) of the countries it had overrun in it’s part of the chase to drive the Germans back. The Russian occupied countries then became the USSR.

@kritiper , That is not quite right. The USSR took over the Russian Empire, which had acquired a large amount of territory over the last few hundred years. Following the Russian Revolution, many of the conquered nations broke away.

@LostInParadise Better check your history books. When the Cold War ended in 1991, the USSR went back to being just Russia.

The USSR existed from 1921 to 1991. The point I was trying to make was that whatever the USSR was before WWII, the Soviets did not go back to those boundaries after the war, but dominated those “satellites” (as the central and eastern European countries came to be called) until 1991.