The district is identical to that of the same in Portuguese Timor, with the following exceptions: during the Indonesian occupation, the subdistrict of Turiscai became part of Manufahi District from Ainaro, and the subdistrict of Hato-Udo became part of Ainaro in exchange.
The district borders Aileu District to the north, Manufahi District to the south, Cova Lima District to the southwest, Bobonaro District to the west, and Ermera District to the northwest.