evidence: In 1912–13 the British Indian government made agreements with the indigenous peoples of the Himalayas of northeastern India to set up the Balipara frontier tract in the west, the Sadiya frontier tract in the east, and the Abor and Mishmi hills and the Tirap frontier tract in the south. Together those tracts became the North East Frontier Agency, which is now Arunachal Pradesh. The northern boundary of the territory (now of the state) determined at that time became known as the McMahon Line; it is about 550 miles (885 km) long and has been a lasting point of contention between India and China.