Russia sold Alaska to the United States in 1867. Part of what is now Poland was in Russia until 1918. The Crimean peninsula was in Russia until 1954 when it was transferred to the Ukraine.
Has Russia lost any land since 1954 that is not inside its current borders?
By Russia I mean the formal state of Russia, whether Tsarist or a republic or a federation. For the avoidance of doubt, I do not mean the USSR. By Russia "having" territory, I mean land formally being administered as part of Russia. So this does not include Berlin, for example.