East Siang district received land from West Siang district in 1989. Ten years later, in 1999, the district was divided into Upper Siang district and East Siang district. The former was inhabited by the Dibu-marang clan, but some padam clan (a subtribe of the Adi) drove them out. Later, padam clans moved to the vicinity of padam mone and balek, respectively, following their close ally Pasi. Later, padams had to withdraw from the mone districts due to an outbreak (said to be spiritual).

Geographical
The district office is situated in Pasighat. The East Siang district is about similar to Nias Island in Indonesia, covering an area of 4,005 square kilometers (1,546 sq mi)