The 2016 census determined a population of zero for the state suburb of Mersey Forest.

The Mersey River passes through the centre of the locality from south to north.

The majority of the locality consists of forest reserves, and it is adjoined on the west, south and east by national parks and conservation areas.

Mersey Forest Road continues south as Route C171 to Rowallan Dam.

[5] It then continues further south with no route number, providing access to the Walls of Jerusalem car park and beyond.