Balgarup River is a river

River

A river is a natural watercourse, usually freshwater, flowing towards an ocean, a lake, a sea, or another river. In a few cases, a river simply flows into the ground or dries up completely before reaching another body of water. Small rivers may also be called by several other names, including...

 in Western Australia

Western Australia

Western Australia is a state of Australia, occupying the entire western third of the Australian continent. It is bounded by the Indian Ocean to the north and west, the Great Australian Bight and Indian Ocean to the south, the Northern Territory to the north-east and South Australia to the south-east...

 that has its headwaters South East of Kojonup

Kojonup, Western Australia

Kojonup is a town located 256 km south-east of Perth, Western Australia along Albany Highway.The name Kojonup is believed to refer to the "Kodja" or stone axe made by Indigenous Australians from the local stone....

 just below Byenup Hill.

The river flows is a north westerly direction crossing Albany Highway

Albany Highway

Albany Highway is a generally northwest-southeast highway in the south of Western Australia which links the state's capital Perth with its oldest settlement, Albany. The highway is approximately in length, is designated State Route 30 and separates Western Australia's Great Southern region from...

 south of Kojonup

Kojonup, Western Australia

Kojonup is a town located 256 km south-east of Perth, Western Australia along Albany Highway.The name Kojonup is believed to refer to the "Kodja" or stone axe made by Indigenous Australians from the local stone....

 then through the town of Muradup

Muradup, Western Australia

Muradup is a small town in the Great Southern region of Western Australia located between Kojonup and Boyup Brook. The town is situated along the Balgarup River....

 and continues in th north west direction until it joins the Blackwood River of which it is a tributary

Tributary

A tributary or affluent is a stream or river that flows into a main stem river or a lake. A tributary does not flow directly into a sea or ocean...

.

The only tributary to the Balgarup river is Mandalup Brook.

The name originated from Aborigine

Australian Aborigines

Australian Aborigines , also called Aboriginal Australians, from the latin ab originem , are people who are indigenous to most of the Australian continentthat is, to mainland Australia and the island of Tasmania...

 language and is thought to mean place of the Blackboy trees

Xanthorrhoea preissii

Xanthorrhoea preissii , with the common name Balga, is a widespread species of perennial monocot in Southwest Australia. This plant, and other members of the genus Xanthorrhoea, are also known as grasstrees...

.The first person to chart the river was a surveyor named Alfred Hillman in 1840.