The river flows through Chubut Province for approximately 800 kilometres to reach the Atlantic Ocean at Engaño Bay near Rawson. The main arm of the Chubut originates in Carreras at the Andes in Río Negro Province, although its basin covers a large area of the western Andean foothills between Bariloche and Esquel. It is also fed by the Chico River. The many branches join some distance before the small town of Piedra Parada, where the terrain becomes the flat plain characteristic of Argentine Patagonia. It flows east and passes by the town of Paso del Sapo where it turns south east and through relatively unpopulated central Chubut. It meets the major Highway 25 and turns east once again.
Some 120 km west of Trelew the river has been dammed by a 255 m long concrete dam. The dam, named after palaeontologist Florentino Ameghino, was planned and directed in 1943 by engineer Antonio Domingo Pronsato; work started on 19 April 1963. The artificial lake covers 70 square kilometres. The plant, which uses a 56 m high waterfall with a flow of 150 m³/s and three turbines, provides energy to Pico Truncado, Caleta Olivia, Comodoro Rivadavia and the lower Chubut Valley.
The river is generally shallow and its water flow can vary from 4 to 30 m³/s between drought and flood. The flooding made the lands alongside it fertile and important for agriculture. The river is a popular trout fishing destination; a license is needed.
In the 19th century, Welsh settlers arrived in Chubut and established a colony, "Gwladfa Gymraeg"/"Colonia Gales", in the valley of the Chubut river. Today, the Welsh language and Welsh tea houses are common within several towns, many of which have Welsh names such as Dolavon, Trelew, etc.