India has seven principal mountain ranges. Among these, pride of place belongs naturally to the Himalayas - the abode of the snows. The Himalayas are the world's youngest and largest east-west mountain chain and stretch some 2,500 kilometres (1,600 miles) in an arc across the top of the Indian subcontinent.The mountains were fonned between 50 and 60 million years ago. The most recently formed are the lower foothills known as the Shivaliks which consist of sedimentary rock very susceptible to erosion. Beyond the Shivaliks lie the Himachal, the Lesser Himalayas. It is in these ranges that the most celebrated hill stations are found: Shimla, Dalhousie, Mussoorie, Nainitaland, Darjeeling. Like most northern hill stations they are situated between 1,230 metres and 2,460 metres (4-8,000 feet) and the peaks on which they stand would no doubt have qualified as mountains rather than mere hills were it not for the Himadri, the Great Himalayas, beyond. In the Himadri are Everest and Annapurna, which lie within Nepal, and Kanchenjunga, Nanga Parbat and Nanda Devi, which fall within the boundaries of India. From the Himalayas flow the great rivers of the Punjab, as well as the holiest river of all, the Ganga or Ganges.The Himalayas are the highest mountain range in the world but the lesser known Aravalli is one of the oldest. The Vindyas divide the wide Genetics plain of the north from peninsular India, the triangular plateau which forms the southern part of the country. They stretch over 1,000 kilometers (627 miles) across the top of the peninsula at an average altitude of 300 meters (974 feet) and form one of the country's main watersheds.

The Satpuras, another ancient mountain system, run south of, and more or less parallel to, the Vindyas. They have one hill station, Pachmarhi, which is found near the highest point in the range, Dhupgarh at 1,350 metres (4,429 feet). 'Sat' means seven and 'pura' folds, referring to the lines of hills which make up the Satpuras.

More impressive than these are the Sahyadris, the Western and Southern Ghats, which run for 1,600 kilometers (1,000 miles) down the western edge of India to the southernmost tip of the country. The popular hill stations of the former Bombay Presidency are in the Western Ghats. The word 'ghat' itself means pass and here are the passes from the higher peninsula down to the coast. The Sahyadris rise diff-like on the western, coastal side and catch the heavy monsoon rains. Their more gentle eastern slopes consequently have a much drier climate. The hills become progressively higher towards the south. The highest point is reached in the spectacular Nilgiri Hills, literally 'blue mountains', the site of Ootacamund which stands at the foot of the 2,637-metre- (8,615-foot-) high Dodu Betta Peak.

The last great range of India is the Purvachal, or Eastern Mountains, running along the Indo-Burmese border in northeastern India. These remote hills again have no hill station. The great center for the British in the northeast was Shillong, the capital of British Assam. Shillong lies in the Khasi Hills, which geologically belong more to peninsular India than to Purvachal. Shillong is now the capital of the recently formed state of Meghalaya which means 'abode of the clouds'. Until recent deforestations began changing the climate nearby Cherrapunji was renowned as the wettest place in the world.

Beyond the Nilgiris are the southernmost Sahyadris - the Anaimalai or Elephant Hills, the summits of which are said to resemble elephant heads. Also here are the Palni Hills, site of the hill station Kodaikanal, and the Elamalai or Cardamom Hills which are named after their cardamom plantations.

On the opposite side of the peninsula, the Eastern Ghats run southwest from the Mahanadi River until they meet the Nilgiri Hills. These ghats have summits over 1,000 metres (over 3,200 feet), but are devoid of hill stations. To the southeast of them are the Shevaroy Hills and the hill station of Yercaud.