Section 18(1)(a) in The State Of Arunachal Pradesh Act, 1986
(a)there shall be a common High Court for the States of Assam, Nagaland, Meghalaya, Manipur, Tripura, Mizoram, and Arunachal Pradesh to be called the Gauhati High Court (the High Court of Assam, Nagaland, Meghalaya, Manipur, Tripura, Mizoram and Arunachal Pradesh) (hereinafter referred to as the common High Court);