The China-Russia border is the longest international border in the world, stretching over 4,200 kilometers (about 2,600 miles). It runs from the Mongolian border in the west to the Sea of Japan in the east, separating the two countries. This border features diverse landscapes, including mountains, rivers, and forests. The border has significant historical and economic importance. It facilitates trade and cultural exchange between China and Russia, with several key crossings allowing for the movement of goods and people. Both nations have worked to strengthen their relationship, enhancing cooperation in various sectors along the border.