Sandy Hole Pass sits beside the East Dart River in an area of Dartmoor that was heavily mined for tin. The look of the area is man-made and its reason was in order to narrow the East Dart River to create a faster flow of water. Creating the granite walls did this, and allowed the miners to use the river to carry away the sand and wastes from their tin mining. It is believed that Dartmouth harbour silted up because of the mining at Sandy Hole.