The Obako mountains plant region refers to the area which is surrounded by Totsukawa Valley on the east and by the boundary of Wakayama Prefecture on the south, on the north and on the west; the area is further divided into Obako section and Hatenashi section by Jinno-gawa River.
伯母子山地植物地区は東を十津川渓谷、南北と西を和歌山県境稜線で画された地域を指し、神納川を境にさらに伯母子区および果無区に細分される。