Tramontane is an adjective that means traveling to or situated on the other side of the mountains. 

The Latin prefix T-R-A means ‘across’ or ‘beyond,’ while the Latin word mons (MONS) means ‘mountain’. If something is located transmontane, it is located ‘across the mountains.’ 

After spending several weeks on the eastern side of the Alps, it never occurred to me how lovely the other side of the mountains were. Once we traveled there, I was stunned by the beauty of the tramontane region.