There actually is a russian phrase "на чужбине", "на чужой земле" (in a foreign land) where "на" is used when talking about another country. I guess using diffe

There actually is a russian phrase "на чужбине", "на чужой земле" (in a foreign land) where "на" is used when talking about another country. I guess using different prepositions is something historical, so "на" is not used anymore, but it is left in some set phrases.