Royalla is a rural locality on the border of New South Wales and the Australian Capital Territory. The area takes its name from the nearby Mount Rob Roy, and was originally a railway settlement on the Bombala railway line known as Rob Roy and changed to the current name in 1905. Modern Royalla is a large rural locality east of the Monaro Highway. The border with the ACT follows the western boundary of the easement of the former railway line to the east of the highway. The town was served by a railway station until 1975. The NSW part of Royalla had a population of 984 at the 2016 census.

The Bombala railway line is a branch railway line in the south of New South Wales, Australia. The northern part of it forms part of the main line from Sydney to Canberra, but the southern part is closed. It branches off the Main South line at Joppa Junction, south of Goulburn. The line is used by NSW TrainLink Xplorer services running between Sydney Central and Canberra station.