It is thought that the fortifications were built first (pre-Roman Iron Age), then the broch (around 100 to 140 CE) followed by the settlement under the pax Romana of about 140 to 180 CE. The broch and some of the smaller structures were excavated numerous times before 1879. All finds are now in the National Museum of Scotland. These consist of a stone whorl, piece of jet ring, an amber bead, fragment of translucent glass bracelet, bones, teeth and oyster shells.
The fort consists of a double rampart up to 4.5 metres in height in places and covering an oval area of around 135 metres by 75 metres. The overall diameter of the broch is around 27 metres which is very large for one of these sites.