The geography of Thimphu is defined by its central river valley.
* **Wang Chhu (Raidāk River):** This major river flows directly through the heart of the Thimphu valley. It is a vital water source, shaping the settlement patterns of the district. Further downstream, it powers several of Bhutan's critical hydroelectric plants before flowing into India. * The riverbanks within the city are relatively steep and are largely preserved in their natural state, though small parks and walking paths have been developed in select urban stretches.