Part of the Heart of Neolithic Orkney World Heritage Site, the Standing Stones of Stenness and the Ring of Brodgar Stone Circle are two late Neolithic or early Bronze Age ceremonial stone circles, both situated on a narrow strip of land called the Ness o' Brodgar between Lochs Harray and Stenness in western Orkney. Collectively the Standing Stones of Stenness and the Ring of Brodgar Stone Circle, Skara Brae Prehistoric Village and Maeshowe were designated as a UNESCO World Heritage Site in 1999.

Situated on the south-eastern shore of Loch Stenness, the Standing Stones of Stenness are the earlier of the two monuments; radio carbon dating has shown that its megaliths date from at least 3100 BCE, making it one of the earliest stone circles in Britain. The Standing Stones of Stenness are noteworthy for their sheer size - standing at a maximum height of 6 metres they are visible for miles around. Unfortunately only four of the ring's original 12 megaliths now remain.

Situated approximately one mile to the west of the Standing Stones of Stenness is the Ring of Brodgar, generally thought to have been built between 2500 BCE and 2000 BCE. Built in a true circle and measuring 104 metres in width, it originally contained 60 megaliths, but today only 27 survive. The stones vary from 2.1 metres to a maximum of 4.7 metres in height. Around the Ring of Brodgar are at least 13 prehistoric burial mounds dating from 2500-1500 BCE.

Both the Standing Stones of Stenness and the Ring of Brodgar are surrounded by deep circular ditches typical of henge monuments. The earth from these ditches would at one time have been used to create high banks (also typical of henges) that enclosed both sites, although no trace of either outer bank remains today.

The Standing Stones of Stenness and the Ring of Brodgar are believed to have once formed part of an enormous prehistoric circle complex, much of which has long since disappeared. Lying to the north-west there was once another henge known locally as the Ring of Bookan, although no easily visible signs of this henge remain today.