Thimphu is defined by the **Wang Chhu** (also known as the Raidāk River in its lower courses), a major river that carves through the center of the Thimphu Valley.
The river is central to the city's geography, with the urban layout built along its western banks. While not typically used for boating due to its fast-flowing, rocky nature, the Wang Chhu provides a scenic backdrop for the city, bordered by parks, traditional bridges, and the majestic Tashichho Dzong.