The road forks at the grubby town of Chungthang, 40km north of Mangan – the road to the right climbs rapidly to the group of small settlements of Lachung, the “big pass”, a mere fifteen kilometres west of Tibet. Across the river from the main cluster of settlement, Lachung Monastery is a two-storey Tibetan-style gompa belonging to the Nyingmapa sect, and worth visiting especially for its wonderful murals.
As the road north ascends past yak pastures, it enters the Shingba -Rhododendron Sanctuary, announcing the start of Yumthang (3645m), 25km north of Lachung, with spectacular rock and ice pinnacles towering to 6000m on either side. This beautiful tree lined valley does not have accommodation but boasts somewhat neglected hot sulphur springs. A pleasant purpose-made walking trail leads 10km along the valley floor, back to the sanctuary gates – due to the high altitude and problems with acclimatization, descent rather than ascent is recommended. Past Yumthang, the road continues up the valley and emerges on the high plateau land at Yumesamdong or Zero Point (the end of the road), at an altitude of 4770m with a backdrop, weather permitting, of the snowy sentinels along the Tibet border.