The Ganga River basin, India's largest, includes approximately 25 percent of the nation's area; it is bounded by the Himalayas in the north and the Vindhya Range to the south. The Ganga has its source in the glaciers of the Greater Himalayas, which form the frontier between India and Tibet in northwestern Uttar Pradesh. Many Indians believe that the legendary source of the Ganga, and several other important Asian rivers, lies in the sacred Mapam Yumco Lake (known to the Indians as Manasarowar Lake) of western Tibet located approximately 75 kilometers northeast of the India-China-Nepal tripoint. In the northern part of the Ganga River basin, practically all of the tributaries of the Ganga are perennial streams. However, in the southern part, located in the states of Rajasthan and Madhya Pradesh, many of the tributaries are not perennial.
