One of the nine Glens of Antrim and designated an area of outstanding natural beauty.
It is one of the narrowest glens stretching from the seashore at Cushendun to the foothills of Trostan, the highest peak on the Antrim plateau. It is a steep sided glen with bog and peatland covering the top of the hills, the river Dun (brown river) drains the valley fed by numerous streams and burns as it makes its way down to the sea. It rises high in the valley in the peatland of the Orra
mountain hence the name dun meaning brown. Because of the steep nature of the glen it is subject to flash floods and over the years numerous landslides. The biggest in recent years, happened in 1963 when a huge burst in the townland of Brocaghs tore down the valley bringing hundreds of tons of moss and debris. The glen is a patchwork of small farms, most have access to a mountain area on the top sides of the valley on which flocks of sheep graze. On the lower areas of the valley sheep are also the main livestock, intermingled with small herds of suckler cows. The Forestry Service of N. I. acquired a large track of the mountain area at the top of the glen c1960, now known as Slieveanorra Forest and it is planted with conifers.