A nature reserve situated 2 miles (3 km) west of Sorbie in The Machars of Dumfries and Galloway, Dowalton Marshes occupies the site of the former Dowalton Loch, which was drained in 1863 to provide additional agricultural land, although parts were unsuitable for cultivation and therefore remain as marshland. Extending to 111 ha (274 acres), this was once the largest loch in The Machars and contained a number of ancient lake dwellings known as crannogs. The most notable of these is Miller's Cairn.
Dowalton Loch Site of Special Scientific Interest (SSSI) was designated in 1984 and extends to 125 ha (308 acres). It represents a mosaic of wetlands, woodland and scrub, which provides valuable wildlife habitat. The drier part of the site attracts large flocks of redwing and fieldfare during autumn and winter, together with several species of warbler and many other small passerines, which are prey to hen harriers. The area floods in winter, attracting otter and large numbers of water birds, including teal, water rail, widgeon and whooper swans.
The Scottish Wildlife Trust acquired 6.5 ha (16 acres) of the Marshes as a formal reserve in 1993.
