Nepal is of roughly trapezoidal shape, 800 kilometres (497 mi) long and 200 kilometres (124 mi) wide, with an area of 147,181 km2 (56,827 sq mi). See List of territories by size for the comparative size of Nepal. It lies between latitudes 26° and 31°N, and longitudes 80° and 89°E.
Nepal is commonly divided into three physiographic areas: Himal, Pahad and Terai. These ecological belts run east–west and are vertically intersected by Nepal's major, north to south flowing river systems.
The southern lowland plains or Terai bordering India are part of the northern rim of the Indo-Gangetic Plain.Terai is a lowland region containing some hill ranges. They were formed and are fed by three major Himalayan rivers: the Kosi, the Narayani, and the Karnali as well as smaller rivers rising below the permanent snowline. This region has a subtropical to tropical climate. The outermost range of foothills called Sivalik Hills or Churia Range cresting at 700 to 1,000 metres (2,297 to 3,281 ft) marks the limit of the Gangetic Plain, however broad, low valleys called Inner Tarai Valleys (Bhitri Tarai Uptyaka) lie north of these foothills in several places.