Geography · Ch 2 — Structure and Physiography
The North and Northeastern Mountains
The North and Northeastern Mountains
The photograph shows a single, towering Himalayan peak rising sharply against a dark sky. The mountain is snow-covered and jagged, with steep ridges and a pronounced summit that cuts cleanly against the backdrop. There are no people, buildings, roads, or vegetation visible — the frame is filled almost entirely by rock and ice. The dark sky and the stark contrast with the bright snow make the peak feel remote and severe, as if it stands far above the surrounding landscape.
What the image is really teaching is the character of the Great Himalayas, not their location. The jagged, sharp crestline is the signature of a young fold mountain — the peaks have not yet been worn down by millions of years of erosion, so they remain high, angular, and dramatic. The heavy snow cover reinforces the altitude: these are ranges that rise well above the snowline, and their height is what makes them a climatic divide, intercepting moisture and creating rain shadows. The dark sky and the sheer verticality of the peak also convey the sense of a wall — the same "strong and long wall" that separates the Indian subcontinent from Central and East Asia. …
The Himalayas are far more than a mountain chain — they are a complete divide. This section introduces the North and Northeastern Mountains of India, which include the Himalayas and the hills of the Northeast, and explains how these ranges are oriented, sized, and what they separate.
The Two Components
The North and Northeastern Mountains consist of two broad units: the Himalayas and the Northeastern hills. The Himalayas themselves are not a single ridge but a series of parallel mountain ranges running alongside one another. Among the important ranges named here are the Greater Himalayan range, which itself includes the Great Himalayas and the Shiwalik range.
Orientation of the Ranges
The direction in which these ranges run is not uniform across the country. It changes as you move from west to east:
- In the northwestern part of India, the general orientation is from northwest to southeast.
- In the Darjiling and Sikkim regions, the Himalayas lie in an east–west direction.
- In Arunachal Pradesh, the ranges run from southwest to northwest.
- In Nagaland, Manipur and Mizoram, they take a north–south direction.
So the same mountain system swings through different orientations depending on the region — a fact worth remembering because it reflects the geological forces that shaped each segment.
Dimensions of the Great Himalayan Range
The Great Himalayan range is also called the central axial range. Its approximate length is 2,500 km, measured from east to west. Its width is not constant; it varies between 160 km and 400 km from north to south. These figures give a sense of the sheer scale of the barrier.
The Himalayas as a Divide
Looking at a map, the Himalayas stand almost like a strong and long wall between the Indian subcontinent on one side and the countries of Central and East Asia on the other. But the book stresses that this wall is not merely physical. The Himalayas act as a climatic, drainage and cultural divide as well.
- As a physical barrier, they separate India from its northern neighbours.
- As a climatic divide, they block cold winds from the north and trap the monsoon, shaping the weather of the subcontinent.
- As a drainage divide, they separate the river systems that flow south into India from those that flow north into Central Asia. …