The locality is bounded to the west by the ridge of the Many Peaks Range and to the south-east loosely by Baffle Creek at the foot of the Gwynne Range (in the neighbouring locality of Mount Tom to the west).[3]
The north-west corner of the locality is within Bulburin National Park which extends into neighbouring locality of Boyne Valley. A second disconnected part of Bulburin National Park incorporates part of the western edge of Colosseum, extending into Boyne Valley and neighbouring Gindoran to the south-west.[3] The Mount Colosseum National Park is in the east of the locality.[3]
Apart from the protected areas, the land use is a mixture of plantation forestry (mostly in the south-west of the locality) and grazing on native vegetation. The residential area is mostly around the Bruce Highway in the north of the locality.[3]
There are a number of mountains in the locality including (from north to south):
The Polmaily State School War Memorial is at the back of the former Polmaily State School site in bushland (24°22′53″S151°31′18″E / 24.38148°S 151.52165°E / -24.38148; 151.52165). It commemorates 18 pupils of the school who served in World War I. It was unveiled on Friday 13 December 1918 by Elizabeth Smith, wife of the Presbyterian minister Thomas Smith, who also spoke at the ceremony. The couple had two sons who served in the war, Sydney Francis and Archibald Philip.[13][14] The memorial was organised by Charles Row Vanderwolf whose two sons Charles Jakeman and Harry served with Charles Jakeman killed.[15][16][17] The memorial is an obelisk 11 feet 6 inches (3.51 m) high and was made from Queensland freestone with marble panels by stonemason John Thomas Satchwill of Knight Marble Works in Maryborough.[18][19] Although the school land is now used for other purposes, a 809-square-metre (0.200-acre) land parcel has been set aside as a reserve for the war memorial with the Gladstone Regional Council appointed trustee.[12]
In the 2016 census, Colosseum had a population of 218 people.[22]
In the 2021 census, Colosseum had a population of 184 people.[1]
Education
There are no schools in Colosseum. The nearest primary schools are Miriam Vale State School in neighbouring Miriam Vale to the north and Lowmead State School in neighbouring Lowmead to the southeast. The nearest secondary schools are Miriam Vale State School (to Year 10), Rosedale State School (to Year 12) in Rosedale to the south, and Tannum Sands State High School in Tannum Sands to the north-east.[3]
^"NEW STATE SCHOOLS". Daily Standard. No. 4550. Queensland, Australia. 12 August 1927. p. 10 (3 p.m. EDITION). Retrieved 13 July 2021 – via National Library of Australia.