Fort Archambault (Sarh) was founded by the colonial French Equatorial Africa, for returnees from the labour camps associated with the construction of the Congo-Ocean Railway.

[1] Sarh is located on the Chari River, 350 miles (560 km) southeast of the capital city N'Djamena.

Like other parts of southern Chad and the East Sudanian savanna, Sarh has a typical tropical savanna climate (Köppen Aw), with a wet season and a dry season and the temperature being hot year-round.

Sarh receives 969.3 millimetres (38.16 in) of rain over 86 precipitation days, with a distinct wet and dry season like most tropical savanna climates.

It is a center for the cotton industry, due to its warm and seasonally wet climate.