Clarence is a location in New South Wales, Australia. It was originally a railway outpost on the original railway line across the Blue Mountains, but by 1908 when Clarence was used as headquarters for the Ten Tunnels Deviation works, the town population had flourished to over 5,000 residents, the majority being the navvies employed on the deviation works. When the deviation was opened in 1910, the town population quickly fell, despite a new platform built on the new deviation.