Short answers, pulled from the story.
Russia's formal territorial expansion began in earnest after the defeat of Tatar rule at the Great Stand on the Ugra River in 1480. Ivan III and Vasili III then consolidated the Russian state through a series of annexations, including Novgorod in 1478, Tver in 1485, and several other principalities through 1522.
Russia acquired Alaska in 1799 under Paul I, incorporating it into what became Russian America. The territory was sold to the United States in 1867, under Alexander II.
Following its defeat in the Russo-Japanese War, Russia ceded Manchuria, southern Sakhalin, Russian Dalian, and Port Arthur to Japan through the Treaty of Portsmouth. Russia retained the northern portion of the Chinese Eastern Railway from that settlement.
By the end of World War II, the Soviet Union had annexed the Kresy from Poland in 1939, Estonia, Latvia, and Lithuania in 1940, Bessarabia and part of Bukovina from Romania in 1940, parts of Karelia and Pechengsky Raion from Finland in 1940 and 1944, Carpathian Ruthenia in 1944, Tuva, and the Kuril Islands and southern Sakhalin from Japan in 1945.
The Crimean oblast and the city of Sevastopol were transferred from the Russian SFSR to Ukraine on the 19th of February 1954. Russia later annexed Crimea in 2014 following a referendum that Ukraine and most of the international community did not recognize.
On the 30th of September 2022, Vladimir Putin announced the annexation of Donetsk, Kherson, Luhansk, and Zaporizhzhia Oblasts. Russia does not control the full territory of any of the four regions and its government was unable to define the new international borders.