Kasongo, also known as Piani Kasongo, is a town and territory in the Maniema Province in the east of the Democratic Republic of the Congo.

Kasongo lies east of the Lualaba River, northwest of where it meets the Luama River, at an altitude of 666 metres (2,185 ft). Its population is approximately 63,000.

The town is served by Kasongo Airport. Kasongo is connected to the provincial capital Kindu by the 240 kilometres (150 mi) Kasongo Road (a section of National Road 31 (N31)), but the journey takes two days due to the road's poor state. The City also lies on National Road 2 (N2) and Regional Road 629 (R629).

Kasongo is part of the Roman Catholic Diocese of Kasongo.

The town was founded around 1850 to 1860. A few years later it became the capital of the newly founded and short-lived Sultanate of Utetera, established and initially ruled by the Swahili–Arab slave and ivory trader Tippu Tip. His small sultanate was a key trading partner and ally of the Sultanate of Zanzibar in the east.

The area was visited by Henry Morton Stanley in the early 1880s, on his third expedition.

The territory was at the centre of the Congo Arab war and the Batetela rebellion in the 1890s. A century later, Kasongo and its inhabitants were severely affected by the Second Congo War (1998–2003).

• Congolian rainforests
• Cannibalism in Africa § Congo Basin
• Nyangwe

• WorldStatesmen.org: Congo (Kinshasa) Traditional States (including details on states from the Kasongo area and their rulers)