|Name origin: Aboriginal: manilla, maneela, muneela meaning "winding river" or "round about".|
|State||New South Wales|
|Regions||IBRA: New England Tablelands, Brigalow Belt South|
|Part of||Murray–Darling basin|
|- location||south–west of Barraba|
|- elevation||845 m (2,772 ft)|
|Mouth||confluence with the Namoi River|
|- elevation||349 m (1,145 ft)|
|Length||138 km (86 mi)|
|Reservoir||Split Rock Reservoir|
The stream (called a river) rises south–west of Barraba on the northern slopes of the Baldwins Range and drains a portion of the hill country on the western side of the New England highlands and the southern slopes of the Nandewar Range; flowing generally north and east and to the town of Barraba. During its course, the stream is joined by five minor tributaries, and flows in a southerly direction towards its confluence with the Namoi River at the town of Manilla; dropping 496 metres (1,627 ft) over its of 138 kilometres (86 mi).
About 10 kilometres (6.2 mi) north of Manilla, Split Rock Reservoir, on the Manilla River, provides one of the main water storages for flood control and irrigation in the Namoi River basin.
|Wikimedia Commons has media related to Macdonald River.|
- "Namoi River catchment" (map). Office of Environment and Heritage. Government of New South Wales.
- Trout and salmon fishing rules