; Mount
Gipmochi at the far end Kupup lies in a transverse depression between the
Dongkya Range that forms the border of Sikkim, and the mountains to the southwest. The Bitang Tso or Elephant Lake, a
glacial lake that is regarded as the source of the
Dichu river, is next to Kupup in the same depressioin. Kupup lies on the higher ground to the northwest of the Bitang Tso lake. Darjeeling superintendent
J. W. Edgar, who surveyed the area for the construction of a road to Tibet in 1874, described Kupup as "a grassy and rather marshy valley". It was said that 1,500 men could encamp in the valley. Fuel and rhododendron scrub were plentiful in the locality. To the northeast of the valley is a steep hill called "Tent Hill", which rises to 1,000 ft. A stream flows down from the Jelep La pass and bends around the Tent Hill to the northwest, and drains into
Menmecho Lake, which was described by Edgar as being especially beautiful. The river flowing from here is called
Rangpo Chu, which is an upstream tributary of the
Teesta River. To the southeast of Kupup, the Bitang Tso is considered the source of the
Dichu River, even though other streams flowing down from the Dongkya Range provide a greater volume of water. Dichu flows southeast until Mount
Gipmochi on the western shoulder of the
Doklam plateau, where it turns south and enters Bhutan. The cart road to
Jelep La on Sikkim–Tibet border, eventually laid by the British, ran on the watershed between Teesta and Dichu rivers. The watershed continues on to the
moraine ridge above Bitang Tso. British explorers noted that, from here on, the road to Jelep La had a gentle ascent, which was no more than above. == Current status ==