The boundary continues to the Caspian Sea, the crest of the Caucasus Mountains (or, less commonly, the river Kura in the Caucasus), and on to the Black Sea.
Batas berlanjut hingga ke Laut Kaspia, puncak Pegunungan Kaukasus (atau lebih jarang, Sungai Kura di Kaukasus), sampai Laut Hitam.