What Countries Have Russia Annexed From 1919 To 1938?

[Lynn_M]

Any at all? Wikipedia has a list, which unfortunately, starts from 1939

https://en.wikipedia.org/wiki/Military_occupations_by_the_Soviet_Union

And when did Russia become the Soviet Union?

[1ozzy]

On 28 December 1922, a conference of plenipotentiary delegations from the Russian SFSR, the Transcaucasian SFSR, the Ukrainian SSR and the Byelorussian SSR approved the Treaty of Creation of the USSR and the Declaration of the Creation of the USSR, forming the Union of Soviet Socialist Republics.

According to google.

[Buenchico]

To say that Russia became the Soviet Union is inaccurate as it ignores the presence of Estonia, Latvia, Lithuania, Byelorussia (Belarus), Ukraine, Moldova, Georgia, Armenia, Azerbaijan, Turkmenistan, Uzbekistan, Kyrgyzstan and Tajikistan within the Union:
http://www.lib.utexas.edu/maps/commonwealth/soviet_union_admin_1974.jpg
which was formed in 1922:
https://en.wikipedia.org/wiki/History_of_Soviet_Russia_and_the_Soviet_Union_%281917%E2%80%9327%29