It is situated at the foot of the Vâlcan Mountains, 16 km (10 mi) northwest of Târgu Jiu.

The commune is composed of seven villages: Bâlta, Bâltișoara, Dobrița, Răchiți, Runcu, Suseni, and Valea Mare.

[3] A village on the Jaleș River named Dăbăcești (now disappeared) mentioned in a document of Dan I dated 3 Octombrie 1385 was the precursor of Runcu.

According to some sources, the local church was founded in the early 17th century by Domnița Florica [ro], daughter of Michael the Brave, who sought refuge in Runcu after the death of her father.

[5] Stone and Bronze Age archaeological finds, as well as artifacts from before the Roman conquest, indicate that Runcu and the surrounding areas were inhabited much earlier.