The Cairngorms are a mountain range in the eastern Highlands

Scottish Highlands

The Highlands is an historic region of Scotland. The area is sometimes referred to as the "Scottish Highlands". It was culturally distinguishable from the Lowlands from the later Middle Ages into the modern period, when Lowland Scots replaced Scottish Gaelic throughout most of the Lowlands...

 of Scotland

Scotland

Scotland is a country that is part of the United Kingdom. Occupying the northern third of the island of Great Britain, it shares a border with England to the south and is bounded by the North Sea to the east, the Atlantic Ocean to the north and west, and the North Channel and Irish Sea to the...

 closely associated with the mountain of the same name - Cairn Gorm

Cairn Gorm

Cairn Gorm is a mountain in the Scottish Highlands overlooking Strathspey and the town of Aviemore. At 1245 metres it is the sixth highest mountain in the United Kingdom...

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Usually referred to as The Cairngorms - this 'modern' use of Cairn Gorm to represent the whole range is potentially misleading - Watson (1975) refers to it as a nickname explaining that the range's former name is Am Monadh Ruadh - the red hills distinguishing them from Am Monadh Liath - the grey hills to the west of the River Spey.
Ironically - naming the range after Cairn Gorm creates a contradiction since Cairn Gorm means Blue Cairn - taking that literally would make the red hills the blue hills changing the old name entirely.