North Devon's Biosphere Reserve is in northern Devon in South West England. Although mainly in the districts of North Devon and Torridge, the reserve also extends into West and Mid Devon. It covers a large area of sea up to in depth off the North Devon coast and includes Lundy island from the shore. The core area is centred on Braunton Burrows, a large sand dune system, which consists of of sand dunes, slacks (troughs between the dunes), grassland, scrub habitat, and a part of the Taw-Torridge Estuary. The reserve's boundary follows the edges of several river catchment areas, mainly of the River Taw and the River Torridge, but also those of smaller rivers running into the sea between Hartland and Lynton. The North Devon Coast Area of Outstanding Natural Beauty lies at the heart of the reserve, while parts of the national parks of Dartmoor and Exmoor fringe the boundaries.