Mount Allyn, Mountain summit in Chichester State Forest, Australia

Mount Allyn is a mountain in the Allyn Range, within Chichester State Forest in the Upper Hunter region of New South Wales. Its summit stands at 1,125 metres AHD, about 8 km south southwest of Careys Peak and 50 km northeast of Muswellbrook. Much of the mountain is covered in Antarctic beech cool temperate rainforest, and snow often falls in winter.

Mount Allyn lies in the Allyn Range within Chichester State Forest, about 8 km south-southwest of Careys Peak and roughly 50 km northeast of Muswellbrook. The sources record no founding date or geological origin for the range, so its documented history is one of land use and access rather than events. Its summit stands 1,125 m above sea level, 13 m above the surrounding terrain.

The name Allyn comes from the Allyn River, which flows below the range; the river and the surrounding forest are part of the traditional country of the Wanaruah (Wonnarua) people. The mountain lies in Chichester State Forest, a working state forest where logging and recreation share the same tracks.

Access to the summit follows a network of forest roads through Chichester State Forest, with conditions varying by season. Winter months occasionally bring snow to the peak, which can affect accessibility.

Much of Mount Allyn is covered by Antarctic beech cool temperate rainforest, a community more usually associated with far southern Australia. The mountain lies about 8 km south-southwest of Careys Peak and some 50 km northeast of Muswellbrook, and snow often falls here in winter.