A side valley beneath Lhotse
Chhukung sits at 4,730 m in the Imja valley, a side branch from Dingboche that dead-ends beneath Lhotse's dramatic south face, reached by trekkers on the Three High Passes or Island Peak itineraries rather than the classic Base Camp route.
Staging point for Island Peak
Chhukung is the last proper village before Island Peak Base Camp (5,100 m), where climbers on the Island Peak itinerary practise crampon and fixed-rope technique the day before their summit attempt on Imja Tse (6,189 m).
The Kongma La pass
Trekkers on the Three High Passes itinerary use Chhukung as a staging point for the Kongma La (5,535 m), the highest and generally most demanding of the route's three technical passes, before descending toward Lobuche.
Close-up Ama Dablam and Lhotse views
The valley offers some of the closest available views of Ama Dablam's south ridge and Lhotse's south face on the entire route, a genuinely different perspective from the more distant views seen at Tengboche or Dingboche.
Why it's not on the classic route
Chhukung requires a dedicated side-valley detour, so only the Three High Passes and Island Peak itineraries include it; trekkers on the classic 14-day route never pass through this valley.
Imja Tsho, the lake above the valley
Imja Tsho, the glacial lake roughly a half-day's walk beyond Chhukung, didn't exist before the 1950s; it formed as meltwater from the retreating Imja Glacier pooled at the glacier's foot and merged into a single lake by the 1970s. It has since grown into one of the fastest-expanding glacial lakes in the Himalaya, reaching about 0.8 km² by 2000 and continuing to expand at roughly 0.02 km² a year, held back only by a natural moraine wall that geologists have flagged as a glacial lake outburst flood risk to villages downstream. In 2016, a UNDP-backed engineering project lowered the lake by 3.4 m through controlled drainage to reduce that risk.