The history of the formation of this district as separate administrative unit dates back to the year 1914, when undivided Siang was a part of the administrative division called Central and Eastern Sections, North East Frontier Track. In 1919, this was re-designated as Sadiya Frontier Track, which was, in 1948, bifurcated into administrative charges called Abor Hill District and Mishmi Hill District.

In 1954, the Abor Hill District came to be known as the Siang Frontier Division, which in turn was renamed as the Siang District in 1965.

Under the provision of the Arunachal Pradesh (Reorganisation of the district) Act No. 3 of 1980 coming into force from June, 1, 1980, the district of West Siang came out as a separate administrative unit under the charge of a Deputy Commissioner. The West Siang district was an unknown land and people lived in isolation during the British rule. It was difficult in the pre-independence days to have access to the interior areas of the present West Siang district mainly due to the lack of communication. The people of the district lived in their scattered hilly abodes in isolation for generations, depending primarily on a sustenance nature of cultivation called Jhum. They exchanged their bare necessities of life through barter trade. The socio-economic and political development dawned in this region only after Independence

Topography of the district is mountainous. The rocky and high hills and mountains with beautiful green valleys and mighty rivers presents a splendid view of scenic beauties and diversities.