Aberdeen was a city in Scotland.
Leela once referred to it as the "granite city", and the Fourth Doctor noted that in fact the granite emitted more radiation into the bodies of the residents of Aberdeen than would a nuclear power plant into its workers. (DW: Underworld)
In 1879, Queen Victoria was travelling to Aberdeen by coach when she was diverted by the Brethren. (DW: Tooth and Claw)
In the late 20th century, the Fourth Doctor dropped off Sarah Jane Smith in what he thought was South Croydon, but was actually Aberdeen. (DW: The Hand of Fear, School Reunion)
In 2007, the battle that began at Canary Wharf stretched as far as Aberdeen. A group of Cybermen hid in an alleyway and used one Cyberman as bait to lure in the Daleks. Once some Daleks arrived, the Cybermen emerged and attacked, managing to rip the dome off of one Dalek's casing. There was also a human casualty, while a report of the fight was taken by a Professor J B Shilling. (DWBIT: Daleks vs Cybermen Special)
Behind the scenes
In real life, though not specified in any script, Aberdeen is specifically in the northeast of Scotland. It is some 570 miles (928 kilometres) distant from Croydon.
