RFE/RL Report on the USSR, September 28, 1990.)
Many mistakenly believe, he continues, that “the present northern oblasts of Kazakhstan were transferred out of the RSFSR to the Kazakh SSR by Nikita Khrushchev during the virgin lands campaign of 1954. This is not so.” Instead, the borders between the two were set after some movement back and forth between 1921 and 1924. After that, they remained stable.
Other areas which Stalin moved to include within the RSFSR or at least the USSR were the Far Eastern Republic which was absorbed into the RSFSR in November 1922, northern Sakhalin which was annexed in May 1925 after Japanese forces were driven out and Wrangel Island which was included within the RSFSR borders in August 1924.
During World War II, Stalin annexed Tannu-Tuva and transformed it into the Tuvin Autonomous Oblast within Krasnodar kray in October 1944. Later in 1961, it became an ASSR. And at the end of the war, Stalin annexed the southern half of Sakhalin and the Kurile islands, what the Japanese still refer to as the Northern Territories.
At the end of the Winter War with Finland, Stalin oversaw the annexation of the southern part of the Karelian isthmus. In 1944, it was transferred from the Karelo-Finnish SSR. In 1944, after the absorption of the three Baltic countries, Moscow took regions of Estonia and Latvia and included them in the RSFSR.
In 1945, on the basis of decisions of the Yalta and Potsdam conferences, the RSFSR was expanded to include the former German East Prussia as the non-contiguous Kaliningrad Oblast. And in 1947, the Finnish city of Pecheneg was included in the RSFSR’s Murmansk Oblast on the basis of the Moscow-Helsinki peace treaty.
Stalin also gave up RSFSR territory to others, primarily in the course of forming union republics in Central Asia, but also part of the North Caucasus which was transferred to the Georgian SSR after Stalin deported many of the nations from this and adjoining territories.
But “the most significant land gift from the RSFSR under Stalin” was the one he gave to Belarus. In 1924-1926, Belarus received almost all of Vitebsk, Mogilev and Gomel oblasts, thereby increasing the territory of the Belarusian SSR “by a factor of three.”