This article describes the geology of the Cairngorms National Park, an area in the Highlands of Scotland designated as a national park in 2003 and extended in 2010. The Cairngorms National Park extends across a much wider area than the Cairngorms massif itself and hence displays rather more varied geology. Other than a small outlier of Old Red Sandstone, there are no younger solid rocks within the National Park. The ice ages of the last 2.5 million years have however left their mark both in terms of erosional and depositional features. Post-glacial features include peat and landslips.