Bhutan is roughly the size of Switzerland. It is located on the southern slopes of the eastern Himalayas, landlocked between the Tibet Autonomous Region to the north and the Indian states of Sikkim, West Bengal, Assam, and Arunachal Pradesh to the west and south. The land consists mostly of steep and high mountains crisscrossed by a network of swift rivers, which form deep valleys before draining into the Indian plains. Elevation rises from in the southern foothills to more than . The highest peak in Bhutan is Gangkhar Puensum at .