The Russian Empire (or Empire of Russia) was a state that existed from 1721 to 1917 in Eastern Europe, Central Asia and North America. The country was the largest contiguous empire in modern history in the mid-19th century. It was dissolved after the February Revolution in 1917. The state was regarded as autocratically ruled and was inhabited by about 181 million people.
The Soviet Union (SU or USSR) was a state in Eastern Europe, Central and Northern Asia that existed from 1922 to 1991. It emerged from the so-called Soviet Russia, the successor state of the Russian Empire. The Russian Soviet Republic formed the core of the union and at the same time its largest part, with further constituent republics added. Their number varied over time and was related to the occupation of other countries (Estonia, Latvia, Lithuania), Soviet republics that existed only for a short time (Karelo-Finlandia) or the division or merger of Soviet republics. In addition, there were numerous autonomous republics or other territorial units with an autonomy status that was essentially limited to linguistic autonomy for minorities.
Before its formal dissolution, the USSR consisted of 15 Soviet republics with a population of approximately 290 million people. At around 22.4 million km², it was the largest territorial state in the world at the time. The Soviet Union was a socialist soviet republic with a one-party system and an absence of separation of powers.
