Tinongtongan is a landlocked barangay, approximately 2 kilometers away from the City Proper known as Poblacion. It is one of the 22 barangays in the Municipality of Diplahan with a total land area of 871.91 hectares. Barangay Tinongtongan is composed of five (5) Puroks including Purok Hillside, Purok Junsay, Purok Bagong Silang, Purok Riverside, and Purok Matinabangon. Its adjacent barangays are Goling to the north, Sta. Cruz is to the east, Songcuya is to the west, and Mejo is to the south. The barangays of Kauswagan, Butong, Manangon, and Lindang are also located within its shared borders. 

The Subanen people were the first settlers of the area. Due to the rushing waters and fallen logs on the ground, the locals found it difficult to walk around. As claimed by the first natives, the place was first called “Tongtongan” because every step demanded extra effort.

In 1936, Alfredo ”Pidong” Jara a young man from the province of Ilo-Ilo arrived in a small town. There, he gathered the Ilonggos to clear and cultivate the land. After a few years, Alfredo “Pidong” Jara's relatives followed him and settled in the area. 

At first, the area was only a “sitio” of Barangay Mejo, within the scope of the Municipality of Malangas. December 19, 1979, Barangay Tinongtongan was also declared to be separated from Barangay Mejo.