Athioda is the north to south political and physical boundary for between Tamil Nadu and Kerala between the end of the Pambar River and the top of Jambumalai peak at the trijunction of Coimbatore and Dindugul Districts and Kerala State. (This peak is locally known as "Chinna Chambu Malai"). The top of the ridge to the west above Athioda is the western limit of the catchment. Thus, the western edge of Manjampatti valley extends up to 2 km into Kerala. Athioda stream joins the Pambar River at the point they both join the Chinnar River at the north west corner of the Valley. West of this point, the Chinnar River forms the boundary between the Indira Gandhi National Park in Tamil Nadu and the Chinnar Wildlife Sanctuary in Kerala. East of this point, the Chinnar river becomes the Amaravati River in Tamil Nadu.