Cornwall

Cornwall was a county of England, and historically part of Damnonium. (TV: The Stones of Blood)

Geography
The county included the town of Stegmoor (AUDIO: Beachhead) and the villages of Bledoe, (PROSE: The Forgotten Son) Porthferiot, (COMIC: The Tansbury Experiment) and Treawtha. (COMIC: The Amateur)

Lizard Point was in Cornwall. There was also a huge stone circle located there, with one stone a perfect circle with a hole in the middle. (PROSE: Invasion of the Cat-People)

Early history
Circa 16000 BC, a Tregannan survey team consisting of Sancreda and Scryfan landed at Cornwall. (AUDIO: The Spectre of Lanyon Moor)

Around 2000 BC, Cessair of Diplos arrived at Boscombe Moor using a segment of the Key to Time in the disguised form of the Great Seal of Diplos. She pretended to be a Celtic goddess, and was accompanied by Ogri. (TV: The Stones of Blood)

The First Doctor, Ben and Polly visited Cornwall in the 17th century. (TV: The Smugglers)

20th century
In the 20th century, the Third Doctor visited Downphilly to observe the launching of a space station. (COMIC: The Enemy from Nowhere) The Fourth Doctor and Romana I arrived at Boscombe Moor in search of one of the disguised segments of the Key to Time, eventually finding it in the possession of Cessair of Diplos. (TV: The Stones of Blood) He also visited Porthferiot while travelling with Sarah Jane Smith. (COMIC: The Tansbury Experiment)

21st century
An archaeological dig at Lanyon Moor in Cornwall was investigated by the Sixth Doctor in 2000, Evelyn Smythe and Brigadier Lethbridge-Stewart. (AUDIO: The Spectre of Lanyon Moor)

Whilst travelling alone and still in the apparent possession of his memories, the Eighth Doctor stopped off in a Cornish village. (PROSE: Rip Tide)

An Independent Republic of Cornwall was newly established by September 2006. In the week leading up to the Cardiff Earthquake, Lord Mayor of Cardiff "Margaret Blaine" revealed that Wales had nearly lost the Blaidd Drwg project to Cornwall, which would have been "unthinkable". (PROSE: The Western Mail, TV: Boom Town)

In the 2000s, when the Daleks had relocated 27 planets to the Medusa Cascade, including Earth, Alan and Maria Jackson were holidaying in Cornwall. (TV: The Stolen Earth)

In 2017, the Eighth Doctor visited Stegmoor and dealt with the survivor of a crashed Voord spaceship. (AUDIO: Beachhead)

Behind the scenes

 * The Second Doctor Volume Two (DWM 528) 1.jpg depicting the Second Doctor hosting a Twitch stream where a viewer by the name of "Duchess" mentions Cornwall.]]Michael Craze, who played Ben Jackson, was born in Cornwall.
 * An illustration by Jamie Lenman for The Second Doctor: Volume Two, printed in DWM 528, featured the Second Doctor hosting a Twitch stream, where a viewer under the username "Duchess" sent the message "CORNWALL 2264 ❤️❤️❤️".