Doklam (Tibetan: འབྲོག་ལམ, Wylie: ‘brog lam, THL: drok lam),[1][a] called Donglang (Chinese: 洞朗) by China,[5][6] is an area in Chumbi Valley with a high plateau and a valley, lying between China's Yadong County to the north, Bhutan's Ha District to the east and India's Sikkim state to the west.

[3][8][9] In 1988, the Chinese People's Liberation Army entered the Doklam plateau and successfully took control of the area.

[14][15] The Imperial Gazetteer of India, representing the 19th century British view of the territory, states that the Dongkya range that separates Sikkim from the Chumbi Valley bifurcates at Mount Gipmochi into two great spurs, one running south-west and the other running south-east.

This spur is cut by the Dichu river (also called Jaldhaka) which originates below the Jelep La pass and enters Bhutan.

The 'southeast spur', called Zompelri ridge, separates Bhutan's Haa District (to the north) from the Samtse (to the south).

Bhutan's claimed border runs along the northern ridge of the Doklam plateau until Sinchela and then moves down to the valley to the Amo Chu river.

[23] John Garver has called the Chumbi Valley "the single most strategically important piece of real estate in the entire Himalayan region".

[24] The Chumbi Valley intervenes between Sikkim and Bhutan south of the high Himalayas, pointing towards India's Siliguri Corridor like a "dagger".

Following the Anglo-Chinese treaty of 1890 and Younghusband expedition, the British established trading posts at Yatung and Lhasa, along with military detachments to protect them.

[26] The Doklam area had little role in these arrangements, because the main trade routes were either through the Sikkim passes or through the interior of Bhutan entering the Chumbi Valley in the north near Phari.

In the ensuing artillery fire, states scholar Taylor Fravel, many Chinese fortifications were destroyed as the Indians controlled the high ground.

[32] Indian security experts mention three strategic benefits to China from a control of the Doklam plateau.

From here, the Chinese would be able to monitor the Indian troop movements in the plains or launch an attack on the vital Siliguri corridor in the event of a war.

After a Bhutanese attack in 1780, a settlement was reached, which resulted in the transfer of the Haa valley and the Kalimpong area to Bhutan.

The eastern part was under the control of independent chiefs, who did face border conflicts with the Bhutanese, losing the Kalimpong area.

[42] In the following decades, Sikkim established relations with the British East India Company and regained its lost territory with their help after an Anglo-Nepalese War.

Continued Tibetan resistance to the acceptance of the Anglo-Chinese treaty eventually led to a British expedition to Tibet in 1904, under the political officer Francis Younghusband.

[49] In the course of the Younghusband expedition, Charles Bell was asked to lead a team investigating a supply route to Tibet through Bhutan, via the Amo Chu valley.

[50][51] The team travelled through Sipchu and Sangbay, and then, along an existing "goat track" on a mountain ridge, went up to the Doklam plateau.

China alleged that Indian troops were crossing into Doklam (which they called "Dognan") from Doka La, carrying out reconnaissance and intimidating Chinese herders.

After several rounds of exchanges, on 30 September 1966, they forwarded a protest from the Bhutanese government which stated that Tibetan grazers were entering the pastures near the Doklam plateau accompanied by Chinese patrols.

Prior to putting forward its claim line, it carried out its own surveys and produced maps that were approved by the National Assembly in 1989.

[78][79] Having turned down China's package deal, in 2000, Bhutanese government put forward its original claim line of 1989.

[91] On 18 June, Indian troops crossed into the territory in dispute between China and Bhutan in an attempt to prevent the road construction.

In a 1949 treaty, Bhutan agreed to let India guide its foreign policy and defence affairs, reminiscent of its protected state status during the British colonial rule.

[98] Contrary to Chinese claim, Nehru's 26 September 1959 letter to Zhou, stated that the 1890 treaty defined only the northern part of the Sikkim–Tibet border and not the trijunction area.

"[109] However, ENODO Global, having done a study of social media interactions in Bhutan, recommended that the government should "proactively engage" with citizens and avoid a disconnect between leaders and populations.

[111] Scholar Rudra Chaudhuri, having toured the country, noted that Doklam is not as important an issue for the Bhutanese as it might have been ten years ago.

[74] On 28 August 2017, it was announced that India and China had mutually agreed to a speedy disengagement on the Doklam plateau bringing an end to the military face-off that lasted for close to three months.

[112][113][114] Chinese forces reportedly returned to Doklam Plateau in September 2018 and had nearly completed their road construction by January 2019, along with other infrastructure.