Kathmandu is located in the northwestern part of the Kathmandu Valley, a massive topographical bowl in central Nepal. The valley covers an area of roughly 600 square kilometers and is completely encircled by four major mountain ranges: the Shivapuri hills to the north, Phulchowki to the south, Nagarjun to the west, and Chandragiri to the southwest. This geographic isolation historically protected the city from invasions and heavily influenced its distinct cultural evolution.
The region's physical geography is characterized by its terraced slopes and complex river systems. The Bagmati River is the most significant waterway in the valley, running southward and serving deeply important religious and ecological functions. Its tributaries, including the Bishnumati, Dhobi Khola, and Tukucha Khola, weave through the urban grid. The soil in the valley, formed by the bed of an ancient lake, is highly fertile, though urban sprawl has significantly reduced agricultural lands.