Nain Singh (21 October 1830 – 1 February 1882), also known as Nain Singh Rawat, was one of the first Indian explorers (dubbed "pundits") employed by the British to explore the Himalayas and Central Asia. He came from the Johar Valley in Kumaon. He surveyed the trade route through Ladakh to Tibet, determined the location and altitude of Lhasa in Tibet, and surveyed a large section of Brahmaputra. He walked "1,580 miles, or 3,160,000 paces, each counted."

During his secret survey of Tibet, Nain Singh was the first non-Tibetan to visit many legendary areas of Tibet, including the Thok Jalung goldfields on 26 August 1867. He would later say that Thok Jalung was the coldest place he had ever visited.

Nain Singh, also known as Nain Singh Rawat, was one of the first Indian explorers employed by the British to explore the Himalayas and Central Asia. He came from the Johar Valley in Kumaon.

After leaving school, Nain Singh helped his father. He visited different centres in Tibet with him, learned the Tibetan language, customs and manners and became familiar with the Tibetan people. This knowledge of the Tibetan language, local customs, and protocol came in handy in Nain Singh's work as a "spy explorer".

Zheng He