Tawang was historically part of Tibet inhabited by the Monpa people. The Tawang Monastery was founded by the Merak Lama Lodre Gyatso in 1681 in accordance with the wishes of the 5th Dalai Lama, Ngawang Lobsang Gyatso, and has an interesting legend surrounding its name, which means "Chosen by Horse". The sixth Dalai Lama, Tsangyang Gyatso, was born in Tawang.
The 1914 Simla Accord defined the McMahon Line as the new boundary between British India and Tibet. By this treaty, Tibet relinquished several hundred square miles of its territory, including Tawang, to the British, but it was not recognized by China.According to Tsering Shakya, the British records show that the border agreed in 1914 was conditional upon China accepting the Simla Convention. Since the British were unable to get China's acceptance, the Tibetans regarded the MacMahon line "invalid".According to Jia Liang, the British did not take possession of Tawang, which continued to be administered by Tibet. When the British botanist Frank Kingdon-Ward crossed the Sela Pass and entered Tawang in 1935 without permission from Tibet, he was briefly arrested. The Tibetan government lodged a formal complaint against Britain. This drew the attention of the British, who re-examined the Indo-Tibetan border and rediscovered that Tibet had ceded Tawang to British India, and attempted to revive the McMahon Line. In November, the British government demanded that Tibet implement the 1914 Simla Accord; this met with rejection from the Tibetan government, which rejected the validity of the McMahon Line. Tibet refused to surrender Tawang, partly because of the importance attached to the Tawang Monastery. In 1938 the British made a move to assert sovereignty over Tawang by sending a small military column under Capt. G.S. Lightfoot to Tawang.This expedition was met with strong resistance from the Tibetan government and local people; a protest was lodged against the British Indian government.
Lightfoot's brief visit elicited a strong diplomatic protest from Tibet but did not cause any territorial change. After the outbreak of the war between China and Japan in 1941, the government of Assam undertook a number of 'forward policy' measures to tighten their hold on the North East Frontier Agency (NEFA) area, which later became Arunachal Pradesh. In 1944 administrative control was extended over the area of the Tawang tract lying South of the Sela Pass when J.P. Mills set up an Assam Rifles post at Dirang Dzong and sent the Tibetan tax-collectors packing. Tibetan protests were brushed aside. However, no steps were taken to evict Tibet from the area north of the pass which contained Tawang town.
The situation continued after India's independence but underwent a decisive change in 1950 when Tibet lost its autonomy and was incorporated into the newly established People's Republic of China. In February 1951, Major Ralengnao 'Bob' Khathing led an Assam Rifles column to Tawang town and took control of the remainder of the Tawang tract from the Tibetans, removing the Tibetan administration.During the Sino-Indian war of 1962, Tawang fell briefly under Chinese control, but China voluntarily withdrew its troops at the end of the war. Tawang again came under Indian administration, but China has not relinquished its claims on most of Arunachal Pradesh including Tawang.
The MLA (August 2016) of Tawang constituency is Tsering Tashi.