The Ruined Castle is a rock formation in the Jamison Valley area of the Blue Mountains, in New South Wales, Australia.

A local elevated point, it is projected from the surrounding bushland, and provides panoramic views of the area.

[2] It is reached by the Federal Pass, which can be accessed via the Scenic Railway, the Furber Steps (which descends from Scenic World) or the Golden Stairs (which descend from the Narrow Neck Plateau, south-west of Katoomba).

[3] The Federal Pass continues south-east from Ruined Castle to Mount Solitary.

Near the track up to Ruined Castle are the sealed openings of several coal mine adits.