^Initially set to take place in 1933, but was delayed multiple times due to Joseph Stalin's policies of collectivization, forced famine and political repression which lowered the population drastically. The only one-day census in the Russian history. Proclaimed defective by the Soviet government in September 1937.
^Took place instead of the "defective" 1937 census.
^The population increased markedly as a result of the Soviet Union's territorial expansion by World War II.