Long Meg and Her Daughters in the context of "Penrith, Cumbria"

A stone circle is a ring of megalithic standing stones. Most are found in Northwestern Europe – especially Stone circles in the British Isles and Brittany – and typically date from the Late Neolithic and Early Bronze Age, with most being built between 3300 and 2500 BC. The best known examples include those at the henge monument at Avebury, the Rollright Stones, Castlerigg, and elements within the ring of standing stones at Stonehenge. Scattered examples exist from other parts of Europe. Later, during the Iron Age, stone circles were built in southern Scandinavia.

The archetypical stone circle is an uncluttered enclosure, large enough to congregate inside, and composed of megalithic stones. Often similar structures are named 'stone circle', but these names are either historic, or incorrect. Examples of commonly misinterpreted stone circles are ring cairns, burial mounds, and kerb cairns. Although it is often assumed there are thousands of stone circles across the British Isles and Europe, such enclosures are actually very rare, and constitute a regional form of henge. Examples of true stone circles include Long Meg and Her Daughters in Cumbria, henges with inner stones such as Avebury in Wiltshire, and The Merry Maidens in Cornwall.

Swinside, which is also known as Sunkenkirk and Swineshead, is a stone circle lying beside Swinside Fell, part of Black Combe in southern Cumbria, North West England. One of around 1,300 recorded stone circles in the British Isles and Brittany, it was constructed as a part of a megalithic tradition that lasted from 3300 to 900 BC, during what archaeologists categorise as the Late Neolithic and Early Bronze Ages.

In this period, the Lake District – a mountainous area in which Swinside is located – saw particularly high levels of stone circle construction, with other notable examples including the Castlerigg stone circle and Long Meg and Her Daughters. The original purposes of these circles is still debated, although most archaeologists concur that they were built for ritual or ceremonial reasons. Constructed from local slate, the ring has a diameter of about 93 ft 8ins (26.8m), and currently contains 55 stones, although when originally constructed there probably would have been around 60. An entrance-exit was included on the monument's south-eastern side, which was defined by the inclusion of two outer portal stones.