On May 13, 1980, Subansiri district was bifurcated into two districts: Lower Subansiri district and Upper Subansiri district. Upper Subansiri district comprised the area occupied by the erstwhile Daporijo sub division and Lower Subansiri district comprised the rest of the area occupied by the erstwhile Subansiri district. On June 1, 1980 the erstwhile Lohit district was divided into two districts: Lohit district and Dibang Valley district. On the same day, Siang district was bifurcated into two districts: East Siang district and West Siang district and Sepla and Bomdila sub divisions of the Kameng district were transformed into East Kameng district and West Kameng district respectively. On October 6, 1984 Tawang district was separated from East Kameng district. In 1987, the ersthwile Tirap district was divided into two districts: Tirap district and Changlang district. On September 22, 1992 the erstwhile Lower Subansiri district was again bufurcated into Lower Subansiri district and Papum Pare district. In June, 2000 Kurung Kumey district was carved out from the erstwhile Lower Subansiri district. On December 16, 2001 Dibang Valley district was bifurcated into Upper Dibang Valley district and Lower Dibang Valley district. On February 16, 2004 Anjaw district was carved out from the erstwhile Lohit district.
Below is the list of 14 districts in Arunachal Pradesh with pincode range and total unique localities per district.
|DIBANG VALLEY||792110||Roing S.O|
|EAST KAMENG||790102||Seppa S.O|
|EAST SIANG||791102||Pasighat S.O|
|KURUNG KUMEY||791118||Palin S.O|
|LOWER SUBANSIRI||791120||Ziro S.O|
|PAPUM PARE||791109||Nirjuli S.O|
|UPPER SIANG||791002||Yingkiong S.O|
|UPPER SUBANSIRI||791122||Daporijo S.O|
|WEST KAMENG||790116||Tenga Market S.O|
|WEST SIANG||791003||Mechuka S.O|