The ancient site of Thornborough Henges in North Yorkshire, England, has been described as “the most important prehistoric site between Stonehenge and the Orkneys”. Though not as well-known as Stonehenge, this prehistoric man-made structure is the largest ritual religious site in the British Isles.
The three henges date from 4,000-3,500 BC and extend for almost 2 km. They form part of a larger complex comprising six large henges located within 10 km of each other, all of similar size and design. Because of the vast area which the complex covers, the henges are best viewed from the air. This is probably why the site is less well-known as it is not so easily visible in the landscape.

This must have been an important sacred site for Neolithic man. In addition to the henges, there are many other large ancient structures including a cursus, standing stones, burial mounds and settlements. Archaeologists believe that hundreds of people may once have flocked to the site in the Neolithic and Bronze Age as a place of worship or a pilgrimage centre set in a ritual landscape.
The three Thornborough Henges are around 550 m apart and extend for more than a kilometre. They are almost identical in size, each having a diameter of approximately 240 metres. Each henge has two large entrances, located directly opposite each other. Rather than standing in a perfectly straight line, there is a slight ‘dogleg’ in the layout which is clearly visible from the air. This has led archaeologists to believe that the henges are aligned with the three stars of Orion’s belt.
Sources
Wikipedia https://en.wikipedia.org/wiki/Thornborough_Henges
Text Alun Harvey