Geography
The Khumbu Valley is the upper Solukhumbu district drainage carved by the Dudh Koshi river and its tributaries, running from Lukla (2,860 m) at its lower gateway to the Khumbu Glacier beneath Everest (8,848.86 m) itself. Nearly the entire Everest Base Camp Trek, every village, monastery, and viewpoint on the classic route, sits within this single valley system, bounded by ridgelines that separate it from the neighbouring Rolwaling and Makalu valleys.
Villages by elevation
Six settlements anchor the standard route through the valley: Phakding (2,610 m), Namche Bazaar (3,440 m), Tengboche (3,860 m), Dingboche (4,410 m), Lobuche (4,940 m), and Gorak Shep (5,164 m). Sleeping-elevation gains between them are uneven: +830 m to Namche Bazaar, +420 m to Tengboche, +550 m to Dingboche, +530 m to Lobuche, and +224 m to Gorak Shep. Three of those exceed the 500 m a night usually advised above 3,000 m, which is why itineraries add rest days at Namche Bazaar and Dingboche.
Sherpa settlement
The valley has been home to the Sherpa people for roughly five centuries, following migration from eastern Tibet across the Nangpa La pass. Namche Bazaar, Khumjung, Tengboche, and Dingboche are all Khumbu Valley settlements built around trade, farming, and, since the mid-20th century, trekking and mountaineering tourism.
Protected status
Almost the entire valley above Monjo falls within Sagarmatha National Park, a UNESCO World Heritage Site since 1979, protecting both the region's alpine ecology and its cultural landscape. Every trekker passes through the Monjo entry checkpoint, where the park permit is checked before the trail climbs toward Namche Bazaar.
Why the whole valley matters to trip planning
The valley works as one continuous corridor, so every Base Camp itinerary, whether 10 days or 21, follows broadly the same line. No route to Base Camp avoids the Khumbu Valley, and even the high-pass crossings on the Three Passes itinerary stay inside this valley system.
Side valleys beyond the main corridor
Three named side valleys branch from the main Khumbu corridor, each home to a different itinerary variation on this site: the Bhote Koshi valley runs northwest from Namche Bazaar toward Thame and the Nangpa La, the historic Sherpa trade route into Tibet; the Imja Valley runs east from Dingboche toward Chhukung and Island Peak; and the Gokyo valley branches west from Dole toward the Gokyo Lakes and the Ngozumpa Glacier, Nepal's longest glacier. A trekker on the classic route goes no further into these side valleys than Dingboche, at the lower end of the Imja Valley, unless their itinerary specifically detours into one.