|County||Tonj South County|
|Elevation||1,404 ft (427 m)|
|Population (2010 Estimate)|
|Time zone||EAT (UTC+3)|
The town is located in Tonj South County, Warrap State, in northwest South Sudan. Its location lies approximately 525 kilometres (326 mi), by road, northwest of Juba, the capital and largest city in the country.
Tonj lies between Rumbek, approximately 153 kilometres (95 mi) by road to the southeast, and Wau, approximately 108 kilometres (67 mi) by road to the northwest. The coordinates of Tong are: 7° 16' 48.00"N, 28° 40' 48.00"E (Latitude: 7.2800; Longitude: 28.6800). The average elevation of the town is approximately 427 metres (1,401 ft) above sea level.
Tonj is a small but growing town in South Sudan's vast interior. Situated between two larger urban centers of Rumbek and Wau, the town is a significant transit point for road travellers. The town's airport has not yet attracted regular airline service.
Tonj is the largest city in Warrap State, one of the ten (10) states that constitute South Sudan. The town and the county where it lies (Tonj County), are the ancestral home to the Dinka along with the Bongo ethnic groups, along with several smaller tribal groups. South Sudanese leader William Deng Nhial was buried in Tonj.
In 2010, it was estimated that the population of Tonj, South Sudan, was approximately 17,340.
South Korean Dr. Lee Tae-seok worked as a Catholic missionary, doctor, teacher and mentor to the people of Tonj. He worked at the leper colony. Lee Tae-seok was responsible for the introduction of a school, the Don Bosco hospital as well as forming the nation's first brass band which brought fame to the town. In memory of Lee Tae-seok, who died of cancer in 2010, the Korean TV network [Korean Broadcasting System|KBS] and the South Sudanese government are working on a joint project called “Smile, Tonj” to rebuild Tonj. 
Three main roads lead out of Tong:
- A43-North leads northwest to Wau, South Sudan
- A43-South leads southeast to Rumbek
- A smaller road leads directly north to merge with the Yirol-Yoynyang Road at Thar Jath
- The town is also served by Tonj Airport