Milam is in the Johar Valley, one of the Bhotia abodes in the Kumaon division, where the river Goriganga originates.

This knowledge of the Tibetan language, local customs, and protocol came in handy in Nain Singh's work as a "spy explorer".

Due to the extreme cold conditions, Milam and other villages of the upper Johar valley are inhabited only for a few months from June to October.

The Schlagintweit brothers planned to send Nain and Mani Singh to Lhasa as well, but in the end, that expedition did not take place.

Adolf Schlagintweit wrote a letter of recommendation for Nain and Mani which they later presented to British survey officials.

[3]: 40 The East India Company, and later the British Empire, sought to form trade relations with Tibet.

Additionally, exploration of Central Asia and Tibet were of particular interest during the Great Trigonometric Survey of India because their geography was largely unknown to the British.

The expedition reached the goldfield at Thok Jalung, mapped the Sutlej river, performed an 850-mile-long route survey, and verified the position of Gartok.

"[10] On 27 June 2004, an Indian postage stamp featuring Nain Singh[11] was issued commemorating his role in the Great Trigonometric Survey of India.

In 2006, Shekhar Pathak and Uma Bhatt brought out a biography of Nain Singh with three of his diaries and the RGS articles about his travels in three volumes titled Asia ki Peeth Par published by Pahar, Naini Tal.

The mountains south of Lake Pangong are named Nain Singh Range in his memory and honour.