Craigellachie (Scottish Gaelic: Chreag Eileachaidh) is a hill lying to the west of the village of Aviemore in Strathspey, in the central Highlands of Scotland. Craigellachie was declared a national nature reserve (NNR) in 1961, and is managed by NatureScot through a lease from Reidhaven Estate. The reserve covers 257 hectares on the eastern slopes of the Monadhliath range of hills, lying between 225 and 535 m above sea level. It is dominated by birkwood (birch woodland), being one of the largest remaining areas of this type of habitat on Speyside, and is also of national importance due to the variety of moths present on the reserve. In addition to the birkwoods, the reserve encompasses a variety of other habitats, such as rocky crags, lochans and open heath with blaeberry.