The district of Lahaul-Spiti in the Indian state of Himachal Pradesh consists of the two formerly separate districts of Lahaul and Spiti. The present administrative centre is Keylong in Lahaul. Before the two districts were merged, Kardang was the capital of Lahaul, and Dhankar the capital of Spiti. The district was formed in 1960. Kunzum la or the Kunzum Pass (altitude 4,551 m; 14,931 ft) is the entrance pass to the Spiti Valley from Lahaul. It is 21 km from Chandra Tal. This district is connected to Manali through the Rohtang Pass. To the south, Spiti ends 24 km from Tabo, at the Sumdo where the road enters Kinnaur and joins with National Highway No. 22. The two valleys are quite different in character. Spiti is more barren and difficult to cross, with an average elevation of the valley floor of 4,270 m (14,009 ft). It is enclosed between 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 170 mm (6.7 inches). It is the fourth least populous district in India (out of 640).