|Mouth||confluence with Hann River|
|Length||68 kilometres (42 mi)|
|Source elevation||616 metres (2,021 ft) |
|Mouth elevation||377 metres (1,237 ft)|
The river rises below the Caroline Range near Mount Lacy and then flows south to the west of Mount Elizabeth then through the Barnett River gorge crossing the Gibb River Road near the Mount Barnett roadhouse before flowing into the Hann River in the Philip Range near Mount Caroline.
It was named by the first European to discover the river, Frank Hann, who had seen it during his expedition to the region in 1898. He named the river after Alfred Barnett, who was the manager of Balmaningarra Station which is situated along the Lennard River.
- "Bonzle Digital Atlas - Map of Barnett River, WA". 2008. Retrieved 13 September 2011.
- "Ausanthrop - Australian Aboriginal tribal database". 2012. Retrieved 29 April 2012.
- Western Australian Land Information Authority. "History of river names". Retrieved 13 September 2011.
- "National River Trust - Inland fish fauna of the Fitzroy river". 2002. Retrieved 13 September 2011.