The topography of Kathmandu is defined by its relatively flat valley floor sitting at an elevation of roughly 1,400 meters (4,600 feet) above sea level. This central plain is interrupted by gentle rolling hills and steep river gorges.
The lowest point in the valley is the Chobhar Gorge (around 1,140 meters), where the Bagmati River exits the basin. The highest points are the peaks of the surrounding hills, with Phulchowki reaching approximately 2,782 meters (9,127 feet). The city itself is built upon ancient lake deposits composed of thick layers of clay and sand, which heavily influenced the local architecture—historically reliant on fired clay bricks—while also making the area uniquely susceptible to soil liquefaction during seismic events.