An internationally-important area of heather moorland and birch forest designated as a nature reserve to the north of the River Dee in Aberdeenshire, the Muir of Dinnet occupies part of the Dinnet Estate, 5 miles (8 km) east northeast of Ballater. Notified as a Site of Special Scientific Interest (SSSI) in 1971 and designated as a National Nature Reserve in 1977, which also includes Loch Kinord and Loch Davan to the north, the area is also noted for its geomorphological importance, with an assemblage of meltwater channels, eskers and related deposits which demonstrate the retreat of an ice-sheet c.12,000 years ago. Diatomite - which formed in shallow lochs left by the glaciers and subsequently dried out - was extracted between 1876 and 1919 by the Nobel Company to make dynamite. There are also areas of raised bog. Features of archaeological interest include hut circles, field systems, a Mediaeval moated homestead and the 9th C. Kinord Cross.
The reserve was formally opened by HRH The Duke of Edinburgh on 19th September 1977 to commemorate the Silver Jubilee of HRH Queen Elizabeth II. Following the expiration of the 25-year management agreement, a new agreement was concluded with the Dinnet Estate and the reserve was re-opened by HRH Prince Charles, Duke of Rothesay, on 20th April 2006. Now managed by the government environmental agency NatureScot, which has constructed way-marked trails around the Nature Reserve, it shares the Burn o' Vat Visitor Centre with The Vat, a remarkable nearby geomorphological feature.