Extensive traces of pre historic man can be found throughout the isle, the vast majority of sites remaining undisturbed. Early settlers of around 3000 B.C. built simple stone shelters – oval or round, the remains of which can now be seen as rubblewalls three to four metres thick although in a tumbledown condition. Some of the shelters are divided into cells, while others have a porch at the entrance for extra protection from the elements. The area at the head of Cullivoe has been identified as one such settlement.
Heel-shaped chambered cairns, with a passage leading into a central burial chamber, are also to be found on the isle and date from the Neolithic period.
The Middle Iron Age is represented by Muckle and Little Heogan at East Biggins and there is a fine Bronze Age burnt mound at Dutch Loch near Hamnavoe.
The remains of the meal roads built with labour paid for by barley meal during the famine years of the early 19th century are still clearly visible.
In the summer of 2000 a small team from Glasgow University conducted a survey and trail excavation of Breis Holm; a possible late Norse monastic community on a sea stack at the mouth of Housa Voe. The remains of eight or nine buildings are still visible there. Maiden Stack may have served as the hermitage.