This chapter draws on field research carried out in Arunachal Pradesh for an account of the McMahon Line from the time of its coming into existence in 1914 to its persistent relevance in the present day. Apart from published scholarship on the subject, this chapter draws on more than a hundred conversations with the people along the Arunachal-Tibet border, and on the author’s access to local administrative documents and locally published and private papers as primary source materials. The aim of the research and the chapter is to foreground the perceptions of the local people who inhabit the border area and to study the response of national policy on the ground. The author is currently working on further corroborating and verifying details for a book on the integration of Arunachal Pradesh in the face of Chinese claims on the region.