The McMahon Line was the border claimed by Britain as the official border between British India and Tibet. The McMahon Line had been drawn up during the Simla Conference of 1914, in which Tibetan, Chinese, and British representatives took part. However, owing to various disagreements with the British, China refused to ratify and recognize any agreements reached at the Conference. As a result, China did not recognize the validity of the McMahon Line border. Thus after the independence of India and the establishment of the PRC in the late 1940s, the issue of the border was not fully resolved. This border was disputed in the Sino-Indian War and the Chinese forces managed to push their border beyond this frontier. Currently the two armies are posted on the Line of Actual Control.

fr:Ligne Mac-Mahon zh:麦克马洪线