The Himalayas have got their name from the Sanskrit word, Himalaya a tatpurusa compound meaning "the abode of snow" (from hima "snow", and alaya "abode"). Kalidas has described the Himalayas, as the `King of mountains, enclosing divinity who stands between the two oceans as measuring rod as were, of the earth.` The Indian Himalayas can be divided into three zones - the Shiwaliks or the Outer Ranges on the southern wing, the Middle Ranges like the Pir Panjal and the Dhauladhar, and the Greater Himalayas with the highest and oldest peaks (many of these are in Nepal).

(1) The Trans-Himalayan Zone is about 40 km in width, containing the valleys of the rivers rising behind the Great Himalyas,

(2) The Great Himalyas or the Central Himalayas comprise the zone of high snow-capped peaks, which are 128 or 144 km from the edge of the plains. Some of the important peaks are Mount Everest which is 8848 metres high, Kanchenjunga is 8580 metres high, Dhaulagiri is 8177 metres high, Mount Godwin Austin is 8611 metres high, and Nanda Devi is 7818 metres high.

(3) The lesser Himalayan Zone is 64 to 80 km wide and having an average altitude of about 3000 metres. This zone, having a height between 1500 and 1600 metres, is covered by evergreen and oak forests, that between 1600 and 2124 metres by coniferous forests of chir, deodar, the blue, pine, oaks and magnolias and that above 2436 metres has birch, spruce, silver fir etc.

(4) The Siwalik Foot-hills extend continuously along the foot of the Himalayas from the Brahmaputra Valley on the East to Potwar plateau and the Bannu plains on the west.

Geologically the Himalayan mountain ranges are not very old. In the Miocene period there was a sea known as the Tethys Sea where we have the Himalayas now. The process of formation of these mountain ranges began in the Oligocene period and continued up to the Post-Pliocene period.

We can also divide the Northern Mountains from West to East into three major regions; and the three regions can be mentioned as Westerns, Central and Eastern. The eastern mountain region consists of those mountains, which lie to the east of the Brahmaputra and along the summit of which runs the frontier of India and Burma. They are divided by a series of river-valleys and covered for the most part with thick forests. The routes through these mountains are difficult. The central Himalayan region extends from Bhutan to Chitral. In Bhutan and Eastern Nepal the rainfall is very high but in Swat and Chitral the rainfall is much lower. The valleys are fertile and cultivated with the aid of irrigation. In the western mountain region the valleys are irrigated and cultivated wherever possible. Along these valleys and over the passes such as the Gomal, the Bolan and the Khyber run the routes to Central Asia and China on one hand and to Persia and the West on the other. The himalayas are the highest mountain ranges in Asia, which includes the Karakoram, Hindu Kosh and a host of minor ranges extending from the Pamir Knot. From the Pamirs in Pakistan to the easternmost bend of the Brahmaputra in Assam, the majestic Himalayas rise across a length of 2,500km. It also seperates India from the Tibetan plateau. The himalayan ranges are the home to about 100 mountain peaks, exceeding 7,200 meters including the famous Mount Everest. From the most ancient times they have attracted pilgrims from all over India, and in their sublime presence people have felt the grandeur and the infinity of the pure spirit.

An estimated 750 million people live in the watershed area of the Himalayan rivers, which also includes Bangladesh. The Himalayas stretch across the nations of Bhutan, china, India, Nepal, Pakistan and Afghanistan. Himalayas also encompass many glaciers, of which the famous Siachen Glacier is also included. This glacier is also the largest in the world outside the polar region. The higher regions of the Himalayas are snowbound throughout the year in spite of their proximity to the tropics. It is the source of three of the world`s major river systems, the Indus Basin, the Ganga-Brahmaputra Basin and the Yangtze Basin. Thus, we can say that the Himalayas gave birth to great rivers Indus and its four tributaries. They form the sources for several large perennial rivers, most of which combine into two large river systems.

The Himalayas, forms the northern barrier of the Indian peninsula, containing the highest elevation of the world. Due to their large size and expanse, has been a natural barrier to the movement of people for many thousands of years. They have prevented intermingling of people from the Indian subcontinent with people from China and Mongolia, causing significantly different languages and customs between these regions. The Himalayas have also hindered trade routes and prevented military expeditions across its expanse. The Himalayas have not only proceed the country from invasion from North, but have also sheltered the vast plains of Northern India from the ice colds winds of the Tibet and have played a great part in determining the climate of North India.

The Indian Himalayas are a hot spot among climbers and trekkers throughout the world that offer some of the finest trekking and mountaineering challenges. Since most of India`s northern boundary lies in these mountains, many areas close to the international borders have been declared off-limits for tourists, especially for foreigners. Territorial disputes and trouble caused by militants are other reasons why access to some parts of the Indian Himalayas is restricted. However, those parts that are accessible include many high mountain ranges; deep valleys; fantastic varieties of vegetation - ranging from dense tropical forests of the lower foothills to alpine and sub-alpine vegetation in the higher reaches and from the rain forests of the east to the desert vegetation in the barren Trans Himalayas.