This watercourse crosses the administrative regions of: Forestry is the main economic activity in the sector; recreational tourism activities are incidental considering the geographic remoteness and lack of access roads.

The surface of the Péribonka East River is usually frozen from the end of November to the beginning of April, however the safe circulation on the ice is generally done from mid-December to the end of March.

The main hydrographic slopes neighboring the Péribonka Est river are: The Péribonka Est river takes its source at the mouth of the Agoseris lake (length: 4.3 km (2.7 mi); altitude: 787 m (2,582 ft)) in the municipality of Eeyou Istchee Baie-James.

The mouth of this lake is located at: From its source, the Péribonka East River flows over 54.8 km (34.1 mi) over an elevation of 217 m (712 ft) entirely in the forest zone, according to the following segments: The Péribonka Est river flows on the East bank of the Péribonka river.

The toponym of “Rivière Péribonka Est” was formalized on December 18, 1986, at the Place Names Bank of the Commission de toponymie du Québec.