Woodhenge is a Neolithic Class II henge and timber circle monument located in the Stonehenge World Heritage Site in Wiltshire, England. It is 2 miles northeast of Stonehenge. Alexander Keiller and OGS Crawford identified Woodhenge in 1925 after an aerial archaeology survey was completed. The site consists of six concentric oval rings of postholes with the outermost ring being about 141 by 130 feet wide. A single flat-bottomed ditch that is 7.9 feet deep and up to 39 feet wide, and an outer bank that is about 33 feet wide and 3.3 feet high surround the rings. With an overall diameter measuring 360 feet, the site had a single entrance to the northeast. The remains of a crouching child were found at the center of the rings, which has been interpreted as a dedicatory sacrifice. After excavation, the remains were taken to London, where they were unfortunately destroyed during The Blitz, making further examination impossible. The remains of a crouching teenager were also found within a grave dug in the Eastern section of the ditch, opposite the entrance.

Most of the 168 postholes held wooden posts, although evidence was found that a pair of standing stones might have been placed between the second and third posthole rings. Recent excavations in 2006 have indicated that there were at least five standing stones on the site, arranged in a cove. The deepest postholes measured up to 6.6 feet deep and are believed to have held posts as high as 25 feet above ground. Those posts would have weighed up to 5 tons each and their arrangement was similar to that of the bluestones at Stonehenge. Further comparisons with Stonehenge were quickly noticed. Both sites have entrances oriented approximately to the midsummer sunrise and the diameters of the timber circles at Woodhenge and the stone circles at Stonehenge are similar. Simple tracings of the plans of Woodhenge, which when folded to find its major axis of symmetry, indicate that the monument may be aligned with the moon. A GPS survey made in 2008 produced the same result.

There are various theories about possible timber structures that might have stood on and about the site but it is likely that the timbers were freestanding, rather than part of a roofed structure. For many years, work on the study of Stonehenge had overshadowed any real breakthroughs in the understanding of Woodhenge. Ongoing investigations, as part of the Stonehenge Riverside Project, are now starting to cast new light on the site and its relationship with neighboring sites and Stonehenge. Theories have emerged in which the sites may all be integrated into an overall layout with roads linking the structures and incorporating the natural features of the River Avon. It has also been suggested that the use of wood vs. stone may have held a special significance in beliefs and practices involving the transformation between life and death.