Thimphu is situated in the constricted, linear valley of the Raidāk River, which is also known as the Thimphu River (''Thimpu Chuu''). While the surrounding hills are in an altitudinal range of  (warm temperate climate between  and cold temperate zone between ), the city itself has an altitude range varying between  and . It is these two variations in altitude and climate which determine the habitable zones and vegetation typology for the valley. The valley, however, is thinly-forested and is spread out to the north and west. At the southern end of the city, the Lungten Zampa bridge connects the east and west banks of the Wang Chuu which flows through the heart of city.