Nestled in the lower Himalayas, Gangtok is situated in the southeastern part of Sikkim. The city's geography is defined by its dramatic elevation changes and lush, verdant surroundings. Gangtok is flanked on its east and west by two prominent streams, the Ro Ro Chu and the Ranikhola, which eventually merge into the mighty Teesta River.
The region is characterized by steep, densely forested mountain slopes featuring temperate and deciduous flora, including bamboo, oak, and various species of orchids. Because the city is built directly onto these steep inclines, the architectural layout is heavily terraced. The surrounding landscape provides crucial natural resources, primarily fast-flowing rivers that are tapped for hydroelectric power, and rich, biodiverse forest ecosystems.