Stonehenge (stōn´hĕnj´), group of standing stones on Salisbury Plain, Wiltshire, S England. Preeminent among megalithic monuments in the British Isles, it is similar to an older and larger monument at Avebury. The great prehistoric structure is enclosed within a circular ditch 300 ft (91 m) in diameter, with a bank on the inner side, and is approached by a broad roadway called the Avenue that connects Stonehenge with the River Avon. Within the circular trench the stones are arranged in four series: The outermost is a circle of sandstones about 13.5 ft (4.1 m) high connected by lintels; the second is a circle of bluestone menhirs; the third is horseshoe shaped; the innermost, ovoid. Within the ovoid lies the Altar Stone. The Heelstone is a great upright stone in the Avenue, northeast of the circle. A number of other ancient features are found in the surrounding landscape, including barrows and the Cursus, an long, elongated oval ditch that predates Stonehenge.
It was at one time widely believed that Stonehenge was a druid temple, but this is contradicted by the fact that the druids probably did not arrive in Britain until c.250 BC In 1963 the American astronomer Gerald Hawkins theorized that Stonehenge was used as a huge astronomical instrument that could accurately measure solar and lunar movements as well as eclipses. Hawkins used a computer to test his calculations and found definite correlations between his figures and the solar and lunar positions in 1500 BC However, as a result of the development of calibration curves for radiocarbon dates, Stonehenge is now believed to have been built in several stages between c.3000 and c.1500 BC, with the main construction completed before 2000 BC Excavation and testing in 2008 established a date of between 2400 and 2200 BC for the erection of the bluestones. Some archaeologists objected to Hawkins's theory on the basis that the eclipse prediction system he proposed was much too complex for the Early Bronze Age society of England.
Most archaeologists agree, however, that Stonehenge could have been used to observe the motions of the moon as well as the sun. Research by the archaeologist Alexander Thom, based on the careful mapping of hundreds of megalithic sites, indicated that the megalithic ritual circles were built with a high degree of accuracy, requiring considerable mathematical and geometric sophistication. More recent speculation on the Neolithic ceremonial and cultural functions of Stonehenge has included its possible use as a center for healing and as a burial ground for a local ruling family. Among the burials near the site have been found remains of a man who was raised near the Alps and a teenage boy raised near the Mediterranean. A discovery in 2008 suggests that Stonehenge was aligned with the winter solstice sunset because local, natural ridges on the Plain that led to its site were so aligned, and other archaeological remains in the surrounding countryside suggest that prehistoric people gathered in the area around the time of the winter solstice. Evidence of a former stone circle with 25 bluestones has been found nearby beside the River Avon; the stones once used there may have been incorporated into Stonehenge. Some of the bluestones produce bell-like sounds when struck; it is unclear, however, how or if this property is connected to their use at Stonehenge.
See G. S. Hawkins, Stonehenge Decoded (1965); H. Harrison and L. E. Stover, Stonehenge (1972); A. Thom, Megalithic Sites in Britain (1967) and Megalithic Lunar Observations (1973); M. Parker Pearson, Stonehenge: A New Understanding (2013).