Ninohe is located in far north-center Iwate Prefecture, bordered by Aomori Prefecture to the north. The northern end of the Kitakami Mountains, the 852.2 meter Mount Oritsume is in Ninohe. Approximately 70% of the city area is mountainous and forested. The upper reaches of the Mabechi River flows through the city. A portion of the city is within the borders of the Oritsume Basenkyō Prefectural Natural Park.