Physical Kunzum Pass or the
Kunzum la (altitude ), from
Chandra Tal, connects the
Lahaul Valley in the west to the
Spiti Valley in the east.
Lahaul (in the west, with Keylong as the main city): Geologically located in the
Himalayas and the
Tibetan Plateau, Lahaul is connected to
Manali in the south through the
Rohtang Pass. Lahaul has three valleys from east to west, the
Chandra Valley (locally known as
Rangloi Valley) after the west-to-east flowing Chandra River, the
Bhaga Valley (locally known as
Ghar Valley) after the north-to-south flowing Bhaga River, and the
Chandra-Bhaga Valley (locally known as
Pattan Valley, and further on as Chenab Valley) west-to-east flowing Chandra-Bhaga River. The confluence of the Chandra and the Bhaga rivers is at Tandi, where is becomes Chandra-Bhaga River. The average elevation of Spiti is significantly greater than that of Lahaul. Lahaul receives much more rainfall than Spiti.
Spiti (in the east, with Kaza as the main town): To the south, Spiti ends from
Tabo, at the Sumdo where the road enters
Kinnaur and joins
National Highway 5. Spiti is barren and difficult to cross, with an average elevation of the valley floor of . It is surrounded by lofty ranges, with the
Spiti River rushing out of a gorge in the southeast to meet the
Sutlej River. It is a typical mountain desert area with an average annual rainfall of only . The Spiti Valley, which follows the course of
Sutlej's tributary west-to-east flowing
Spiti river for about 150 km, is traditionally divided into four main regions or sub-valleys:
Tud (the higher region from Kunzum Pass down to the Spiti River's confluence with Lingti River through high-altitude villages like Losar, Hansa, and Kyoto),
Bhar (the middle region, with the sub-divisional headquarters at Kaza),
Sham (the lower region, with the ancient capital Dhankar and Tabo being the main habitations), the
Pin Valley formed by the Pin River famous for the
Pin Valley National Park. Notable side-valleys are the
Mulang Valley (to the east of
Bara-lacha la between the drainage basins of the Chandra and Spiti rivers), to the west and north of Kaza is
Lingti River Valley (60 km, the longest, often described as a "living geological museum" due to its abundance of shale and fossils dating back 250 million years), the
Parahio River Valley is western tributary of Pin River with Dhar Thango being an important village.
Administrative Lahaul and Spiti district borders the districts of
Kullu,
Kangra, and
Chamba to the south; Chamba to the west;
Jammu and Kashmir and
Ladakh union territories to the north;
Tibet (China) to the east, and
Kinnaur district to the southeast. Lahaul and Spiti district is subdivided into 3 sub-divisions (Keylong, Kaza, and Udaipur), 2
tehsils (Lahaul headquartered at Keylong and Spiti headquartered at Kaza), 1 sub-tehsil at Udaipur under the Lahaul tehsil, 2
community development blocks (Lahaul at Keylong and Spiti at Kaza), 41
gram panchayat (28 in Lahaul and 13 in Spiti). == History ==