Hieun Tsang speaks of the Thathagata's visit to Kiu-lo-to, the ancient kingdom of Kullu. But there is no material evidence to prove his statement true. However there are definite archaeological evidences of institutional Buddhism at Tikka Tambarhar (Pathiyar), Uparali Dari (Kanhiara), Lakhamandal and Chetru in the upper Kangra region since the second century BC.

Rewalsar, located about 20 km south-west of Mandi town, is the most sacred site of Buddhism in Himachal Pradesh. The place possesses a pristine beauty characterised by an emerald green lake, and surrounded by thick woods on all sides. According to a popular legend, the spirit of Guru Padmasambhava dwells on the islands floating in the lake. A majestic pagoda-type monastery looms on the lake-shore, which enshrines a huge stucco image of Padmasambhava. The interior is embellished with murals in mixed Indo-Chinese style. According to legend, it was from this site that Padmasambhava proceeded to Tibet on the invitation of King Sron Btsan Sgampo, to disseminate dharma on the very roof of the world. It was this religion that came to be known as Lamaism. 
Rewalsar is, thus, for the Buddhists what the Mecca is for Muslims.

Beyond Rohtang Pass in Lahaul valley, the Guru Ghantal monastery, located on the confluence of the Chandra and the Bhaga rivers, may be the oldest centre of Buddhist pilgrimage. Downstream, on the left bank of the Chandrabhaga is Tunde village, site of another ancient Buddhist shrine. This shrine is popularly known as Trilokinath and enshrines an image of Boddhisatva Avalokiteshwara. The archaeological evidence found at this site indicate that it had been a significant Buddhist as well as Hindu pilgrimage site in the distant past. Further below at the confluence of the Chandrabagha river and the Miyar stream, is an ancient temple of Marichi Vajravarahi at Udaipur, the earliest surviving relic of Indian Buddhism in the valley. It now enshrines a brass image of Mahishasurmardani. The Buddhists continue to regard this site as a temple of Marichi Vajravarahi. 

Located at around a distance of 4 km from Keylong, the district headquarters of Lahaul and Spiti, perched on the edge of a steep precipice is the Lardang monastery, on the left bank of the Bhaga. A multi-storeyed structure, with white-washed walls and fluttering flags, it houses a series of enormous prayer-wheels which revolve on the slightest touch. At a distance of around 1.5 km from Keylong is the Shashur monastery. It was founded by Lama Dewa Gyasatshe of Ladakh in the 17th century. This monastery is famous for its ritual-plays which are enacted by the lamas while donning masks and exotic costumes. This three-storey tall structure is significant in architectural terms. Due to the narrowness of the site, the complex has been planned vertically, yet it conforms to the ancient mandala concept.

Following the up-stream course of the Chandra river, takes one to the Spiti valley across Kunzamla. Located in the trans-Himalayan arid and arctic zone, this region is characterised by a stark and barren landscape. One of the oldest Buddhist establishments in the Spiti valley, is the monastery at Gungri located deep in the Pin valley. It is the only monastery which belongs to the red-headed sect - the Nyingmapa - founded by Padmasambhava. 

The 'Gem of Himalaya', or the Tabo monastery is the most important, oldest living monastic complex outside Tibet. It was founded in 996 AD, on a symmetrical mandala concept. 

The hill-top Ki monastery is the most prominent feature of the Spiti valley. This monastery is an outstanding example of the monastic architecture which developed during the fourteenth century in the wake of the Chinese influence. The monastery was plundered in the middle of the seventeenth century by the Mongols.In the nineteenth century, it again suffered three brutal attacks. The successive trails of destruction and patch-up jobs have resulted in a haphazard growth of box-like structures, and the complex now resembles a defensive fort. Among the other important monasteries in the Spiti valley are an ancient temple at Lha-lun, and another temple complex at Dhankar. The temples at Dhankar seem to be precariously dangling between heaven and earth !!!

Way below in the Sutlej valley in the Kinnaur area are the temples of the Lotsaba era at Nako. Adorned with mandala murals and stuccoes, these temples enshrine the legendary footprints of Padmasambhava and Parguli devta. Further downstream, on the right bank of the Sutlej, is the famous monastery-village of Kanum. Kanum literally means the 'place of Kangyur'. It was a village rich in scriptural learning in the eleventh century when Rin-chen-bzang-po established a school for scholastic learning here. The Kangyur building is older than the books it houses. The sets of Kangyur and Tangyur found here were printed out of the wooden blocks at Narthang in 1820 AD as replacements of the originals destroyed by the Gurkhas. The inner faces of its walls are richly embellished with many stamped square clay tablets. The Kangyur has had the distinction of playing host, for three years, to Hungarian scholar Alexander Csoma-de-Koros.

Following the down-stream course of the Sutlej, takes one to newly built monasteries at Moorang and Ribba. The pilgrimage to Buddhist sites in Himachal Pradesh come to a fitting conclusion at Parwanoo, the out-post of Himachal towards the Indian plains, where an Ashokan Brahmi inscription was discovered recently. The inscription on the rock known as Kali Pathari records the existence of a shelter-place for the preachers, bhikshus and pilgrims who spread the message of Buddha into the Himalayan interiors and beyond in the remote past.