What is Terai, Pahad & Himal?

Terai, Pahad and Himal are the three broad ecological (or physiographic) belts into which Nepal is conventionally divided. Although Nepal is a small country, it spans an extraordinary altitudinal range — from about 59 metres above sea level in the southern lowlands to 8,848.86 metres at the summit of Mount Everest — within a north–south width of only roughly 150–250 kilometres. Because the great Himalayan arc and its foothill ranges run roughly east–west, the country's landscapes line up in long parallel strips: the flat plains in the south, the hills in the middle, and the snow mountains in the north. These three strips are the Terai, the Pahad and the Himal, and together they shape Nepal's climate, vegetation, agriculture, settlement and culture.

The Terai (also spelt Tarai) is the southern lowland belt, a continuation of the Indo-Gangetic Plain along the Indian border. It is flat, fertile and low (broadly from about 59 m up to a few hundred metres) with a tropical to subtropical climate, and it accounts for roughly 17 per cent of Nepal's land area. The Pahad — the Nepali word for 'hill' — is the central, mid-mountain belt of ridges and valleys, generally below the permanent snowline and broadly spanning altitudes from around 600–1,000 m up to about 3,000–4,000 m, with a subtropical-to-temperate climate. It is the geographic and cultural heart of the country and contains the Kathmandu Valley and most of Nepal's older towns. The Himal is the northern belt of the High Himalaya, containing the perpetual snow and ice and rising above roughly 3,000–4,000 m to the world's highest peaks, including eight of the world's fourteen mountains over 8,000 m. Its climate ranges through subalpine, alpine and nival (snow) zones, and habitation thins out toward the high, arid trans-Himalayan valleys near the Tibetan border.

Crucially, the belts are defined by elevation and ecology rather than by political boundaries, and the proportions of land and people are strikingly uneven. According to Nepal's 2021 census, about 53.7 per cent of the population lives in the Terai, about 40.3 per cent in the Hill belt and only about 6.1 per cent in the Mountain belt — so more than half of all Nepalis live on the lowland belt, while the vast high mountains hold a small minority. This concentration reflects the productivity of the plains and the harshness of the high mountains.

The Terai–Pahad–Himal scheme is the everyday framework Nepalis and the state use to talk about the country. National statistics, development planning, agricultural policy, disaster planning and cultural identity are routinely organised by belt. The Terai is described as Nepal's 'breadbasket' or granary, growing much of the country's rice, wheat, sugarcane and other commercial crops on its flat, irrigable land; the Hills support terraced subsistence farming (maize, millet, rice on irrigated valley floors) plus most of the nation's urban life; and the high Himal supports pastoralism, high-altitude crops such as potato and buckwheat, and increasingly tourism and mountaineering.

The belts also map onto climate and biodiversity. Sal forests, grasslands and lowland national parks such as Chitwan and Bardia (home to tigers, one-horned rhinoceros and Gangetic dolphins) lie in the Terai; temperate broadleaf and pine forests cloak the Hills; and alpine meadows, glaciers and snow leopard habitat occupy the Himal. Travellers and trekkers use the same vocabulary: a typical Himalayan trek climbs out of the Pahad's terraced hills into the Himal's alpine zone, while a wildlife safari belongs to the Terai. The terms are so embedded that Nepali identities and politics are often framed in belt terms — for example the plains-based Madhesi movement of the Terai versus pahadi (hill) communities.

Geographers and scientists, however, use a more refined version of the same idea. The widely cited Land Resource Mapping Project (LRMP, 1986) divides Nepal into five physiographic zones from south to north — Terai, Siwalik (Churia) hills, Middle Mountains, High Mountains and High Himal. In this scheme the Terai and the low Churia foothills make up the popular 'Terai', the Middle Mountains correspond to the Pahad, and the High Mountains plus High Himal correspond to the Himal. Earlier, the Swiss geologist Toni Hagen, who mapped Nepal in the 1950s, proposed an even finer set of north–south units. These scientific subdivisions sit underneath the simpler three-belt model rather than replacing it.

The three names come from different linguistic roots that describe the land itself. 'Terai' (तराई) derives from a Hindustani/Persian root broadly meaning low, damp, moist ground, and originally denoted the low-lying, marshy land at the foot of the hills. The name fits the belt's history: before the mid-20th century much of the Terai was dense, malarial sub-tropical forest, the char kose jhadi ('four-kos-wide forest'), which acted as a natural barrier and was sparsely settled except by the indigenous, relatively malaria-resistant Tharu people. After malaria-control campaigns using DDT from the 1950s onward, large numbers of hill people migrated down and cleared the forests for farmland, transforming the Terai into the country's most populous and agriculturally important belt.

'Pahad' (पहाड) is simply the Nepali word for 'hill' or 'mountain', applied to the mid-hill belt of ridges and valleys between the plains and the high snows. 'Himal' (हिमाल) comes from the Sanskrit hima, meaning 'snow' — the same root that gives 'Himalaya' (hima + alaya, the 'abode of snow'). In Nepali usage himal specifically denotes a snow-covered mountain or a snow range, as opposed to the snow-free pahad. Thus the three names neatly encode the defining feature of each belt: the wet plains, the green hills and the snow mountains.

The three-belt model is also reflected in how Nepal's administrative geography has historically been organised. From 1972 to 2015 the country was divided into development regions that were each meant to span the belts, and provinces and districts are still commonly described as Terai, hill or mountain. While the current federal structure (seven provinces since 2015) does not use the belts as formal units, the Terai–Pahad–Himal distinction remains the basic mental map of Nepal's geography in schools, government and daily life.

A frequent point of confusion is the boundary between the belts, because there is no single sharp line. Between the Terai plains and the Pahad lies a transitional foothill zone — the Siwalik or Churia range (Chure), a band of soft, geologically young hills typically rising to a few hundred up to about 2,000 m. North of the Churia, the Mahabharat Range (Mahabharat Lekh), part of the Lesser Himalaya and roughly 1,500–3,000 m high, forms the front wall of the true hill country. In the simple three-belt model the Churia is usually counted as part of the 'Terai' region and the Mahabharat Lekh as the start of the Pahad, but scientific schemes treat them as separate zones, which is why land-area percentages differ between sources.

Another related term is the Inner Terai, or Bhitri Madhesh (भित्री तराई) — a set of flat, fertile dun-type valleys lying between the Churia and Mahabharat ranges, isolated from the main plains. The best-known are the Chitwan Valley and the parallel Dang and Deukhuri valleys in the west. These valleys have a Terai-like climate and were historically forested and malarial, but they sit inside the hill belt, so they straddle the simple Terai/Pahad division. The word Madhesh (the plains) and the people called Madhesi are likewise associated with the Terai, while pahadi refers to hill people and the high-mountain communities include groups such as the Sherpa.

Finally, the English labels can mislead. 'Hill' (Pahad) sounds modest, but Nepal's hills include rugged country up to 3,000–4,000 m — higher than many countries' mountains — and 'Mountain' (Himal) refers specifically to the snow-and-ice High Himalaya rather than to all elevated terrain. It is also worth distinguishing the ecological belt names from individual named peaks and ranges (for example the Annapurna Himal or Khumbu Himal), where himal is used in the narrower sense of a particular snow massif. Keeping these scales in mind — belt, range and peak — avoids most of the common mix-ups.