The Hinku Valley lies in the Mahalangur section of the Nepal Himalaya in an area that has been recently designated as the Makalu Barun National Park, a sub-district of the Sagarmatha Zone, Solukhumbu District. It is neighboured to the east by the remote and wild Hongu Valley and to the west, in total contrast, by the Dudh Kosi Valley, hosting the Hillary-built airstrip at Lukla and the many busy trekking routes heading for Everest Base Camp. The region was first explored extensively by British expeditions in the early 1950s before and after the ascent of Everest. Members of those teams included Edmund Hillary, Tenzing Norgay, Eric Shipton and George Lowe.
Access from the east can be made using an old and traditional trading route originating in the Arun Valley that crosses the Salpa and then Surkie La Passes. This trail eventually reaches Lukla and the Khumbu by crossing eastern retaining wall of the Dudh Kosi Valley by the Pangkogma La, but if the aim is to reach the upper sections of the Hinku Valley then the only practical option is to head north to the Panch Pokhri lakes before descending steeply to the valley floor at Mosum Kharka. With acclimatisation in mind, the 3,173 metre high Pangkongma La is also probably the best and safest route of access from Jiri or Lukla in preference to the considerably higher and steeper 4,900 metre Zatrawa La.
The Hinku Valley is overloooked by several interesting and attractive summits all rising in excess of 6,000 metres. The twin summits of Kossum Kangurru, 6,373 metres (20,910 ft) rise high above the tea houses at Tagnag, but are nowhere near as impressive as they are when seen from the Dudh Kosi, which is in stark contrast to Tagnagtse (aka Peak 43), 6,770 metres (22,212 ft) that dominates the valley from all directions. However, of all the many fine peaks hereabouts, the one generating the most interest is Mera. Classified as a trekking peak, it comprises three distinct summits, Mera North, 6,476 metres (21,247 ft); Mera Central, 6,461 metres (21,198 ft); and Mera South, 6,065 metres (19,898 ft).
The first ascent of Mera Central was on May 20, 1953 by Colonel Jimmy Roberts and Sen Tenzing Sherpa and the standard route from the north involves high-altitude glacier walking from a base at Khare. The way climbs onto the Mera La, then on and up over a crevassed glacier with superb views of Thamserku, Kangtaiga, Cho Oyu and the Gokyo Valley beyond. An attack camp is usually established on a rocky platform that separates the Mera and Nau Lekh glaciers and the ascent competed on a second day. The final section continues over ever the steepening glacier and a minor bergschrund to a broad summit platform. The panoramic vista from the summit is regarded as one of the finest in the Himalaya and contains no less than five 8,000 metre peaks, the highest mountains in the world, Everest, Lhotse, Makalu, Cho Oyu and Kangchenjunga.