The Yangtze River finds its water source in the south side of Tanggula Mountain in the Qinghai-Tibet plateau. Flowing over 6,300 kilometers (3,915 miles) from west to east, the river moves through steep mountains in the plateau, upland areas and flat plains in hinterland China until it finally reaches the East China Sea where it joins the Pacific Ocean. The Yangtze drains an area of more than 445 million acres taking up one fifth of the total land area of China.