Water is the defining geographical feature of Pasighat.
* **The Siang River:** The lifeblood of the region, the Siang originates in Tibet (where it is known as the Yarlung Tsangpo). It flows dramatically through the Himalayas, passing through Pasighat before entering the plains of Assam, where it meets the Lohit and Dibang rivers to form the mighty **Brahmaputra**. * **Riverine Ecosystems:** The river creates fertile floodplains, temporary sandy beaches (chars) during the dry season, and vast wetland ecosystems that support the area's rich birdlife and agricultural endeavors.
