Kazakhstan is a transcontinental country mostly in Asia with a small western part across the Ural River in Europe. It has borders with the Russian Federation in the north and west, Turkmenistan, Uzbekistan and Tajikistan in the southwest, and China in the far east. The northern border is mostly with Siberia, Russia, so Russia has the longest border with Kazakhstan. Basically, Kazakhstan runs from the Caspian Sea in the west to the mainly Muslim Chinese autonomous region of Xinjiang.