Gloucester River rises within Gloucester Tops, on the eastern slopes of the Great Dividing Range, south east of Gloucester, and flows generally east northeast, joined by six tributaries including the Avon, Barrington, and Bowman rivers, before reaching its confluence with the Manning River, west of Wingham. The river descends 1,150 metres (3,770 ft) over its 102 kilometres (63 mi) course.

The headwaters of the river originate in the World Heritage Barrington Tops region, flowing through the Barrington Tops National Park comprising Antarctic Beech and Southern Sassafras high altitude rainforest. In the middle and lower reaches, the river flows through subtropical rainforest that includes Red Cedar and Rosewood trees.

• Rivers of New South Wales
• List of rivers of New South Wales (A–K)
• List of rivers of Australia

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  The Gloucester River meandering through the Gloucester Valley, viewed from Bucketts Tops, near the town of Gloucester, 2013.
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  Cattle grazing on the banks of the Gloucester River, 1908. Photo courtesy of the NSW State Records Authority.

• "Manning River catchments" (map). Office of Environment and Heritage. Government of New South Wales.
• "Gloucester Tops circuit". Barrington Tops National Park. NSW National Parks & Wildlife Service. Retrieved 16 March 2013.
• "Gloucester Falls walking track". Barrington Tops National Park. NSW National Parks & Wildlife Service. Retrieved 16 March 2013.
• "Gloucester River camping area (eastern section)". Campsites: NSW: Hunter Valley & Coast: Barrington Tops National Park. Explore Australia Publishing. 2010. Retrieved 16 March 2013.
• "Bucketts Walk & Drive". Sports & Recreation. Mid-Coast Council Council. 2011. Archived from the original on 25 April 2013. Retrieved 16 March 2013.

31°58′S 151°59′E / 31.967°S 151.983°E / -31.967; 151.983