The Scottish Highlands were in the northern area of Scotland.
Jamie McCrimmon was a Highland Scot from the mid-18th century who travelled with the Second Doctor, Polly Wright, Ben Jackson, Victoria Waterfield and Zoe Heriot. He also had a couple of adventures with Brigadier Lethbridge-Stewart (TV: The Web of Fear, TV: The Invasion) as well as the Sixth Doctor and Peri Brown. (TV: The Two Doctors, COMIC: The World Shapers) Bernice Summerfield remembered the Seventh Doctor as having a Highlands accent as opposed to the Twelfth Doctor, who had more of a Glaswegian accent. (PROSE: Big Bang Generation)
The Third Doctor was sent to the Scottish Highlands to determine if a rock scientists had found was from Venus. It turned out to be a fraud. (COMIC: Doctor Who and the Rocks from Venus)
Torchwood House was the centre of Torchwood Estate in the Highlands since the 16th century. (TV: Tooth and Claw)
Augustus Pond took his daughter Amy on camping trips to the Highlands. (COMIC: Power of the Mykuootni)