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The Soviet Union was officially established

On this day · 30 December 1922
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On the last days of 1922, four republics signed a Treaty of Union that bound them into the USSR — a state that would last nearly seventy years.

Verified · Seventeen Moments in Soviet History (Michigan State University) — Union Treaty

On 30 December 1922, the First Congress of Soviets of the USSR met in Moscow and approved a Declaration of Union and a Treaty of Union, formally creating the Union of Soviet Socialist Republics. The new state drew together four founding members: the Russian, Ukrainian, Byelorussian, and Transcaucasian Soviet republics.

The documents set out a federal structure — shared institutions, a federal judiciary, common citizenship, and rules dividing budgets among the republics. On paper, the Declaration framed the USSR as a voluntary union of equals, even granting each republic a formal right to secede, a promise that meant little in practice.

The arrangement crystallized in the years that followed; the first Soviet Constitution based on the 1922 treaty was adopted in 1924. From these four republics the USSR would eventually grow to fifteen — a superpower born from a treaty signed in the final hours of a single December day.

4
founding republics
1922
the year

Sources & references

2 references

Well-established. Corroborated by 2 independent sources.

1 Seventeen Moments in Soviet History (Michigan State University) — Union Treaty Academic teaching resource “The Soviet Union was formally created on December 30, 1922 when the first Congress of Soviets of the USSR... approved a Declaration of Union and a Treaty of Union.” soviethistory.msu.edu ↗
2 HISTORY media “On December 30, 1922... the Union of Soviet Socialist Republics (USSR) is established, comprising a confederation of Russia, Belorussia, Ukraine and the Transcaucasian Federation.” history.com ↗
✓ Last reviewed Jun 7, 2026

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