Nations bordering the west flank of the Soviet Unon
The Second World War was concluded by a simultaneous advance of the Red Army from the East and of the Allied Forces from the West converging on Germany. The Iron Curtain was dropped approximately where the two armies met in the middle [an exception was made of Berlin totally included within the Red Army liberated area but divided among the four powers)].
On the Soviet side remained: Poland, Hungary, Czechoslovakia, Bulgaria, Romania and what became the German Democratic Republic (East Germany). Yugoslavia and Albania were a special case. Tito held a non aligned position while running a planned economy and Hoxha, who was more than allied with Stalin’s policies, could not benefit from actual support being geographically separated from the block. The Map from Wikipedia also shows in gray the neutral countries and in bue the NATO allied countries.