Ukrainian Soviet Socialist Republic
Eventually, after the creation of the Communist Party (Bolshevik) of Ukraine in Moscow, a third Ukrainian Soviet government was formed on 21 December 1919 that initiated new hostilities against Ukrainian nationalists as they lost their military support from the defeated Central Powers. Eventually, the Red Army ended up controlling much of the Ukrainian territory after the Polish-Soviet Peace of Riga. On 30 December 1922, along with the Russian, Byelorussian, and Transcaucasian republics, the Ukrainian SSR was one of the founding members of the Union of Soviet Socialist Republics (USSR).
Sloboda Ukraine
After the establishment of the Soviet Union Sloboda Ukraine was divided between the Ukrainian SSR and the Russian SFSR. The early 1930s forced end to Ukrainization in the parts of Sloboda Ukraine located in the Russian SFSR led to a massive decline of reported Ukrainians in these regions in the 1937 Soviet Census compared to the 1926 First All-Union Census of the Soviet Union. The Ukrainian SSR reorganized their part of the region several times before establishing the borders of present-day Kharkiv Oblast in 1932.