The Newgrange Henge or Pit Circle.
There are many other monuments on the ridge of Newgrange besides the great mound itself. Right beside Newgrange is a large circular feature known as the pit circle, discovered during the early stages of the exacvation of the great mound. The pit circle is 100 meters in diameter, about the same size as the circle of standing stones around Newgrange. Five rows of post holes held timber uprights, which may have been lintelled like the famous Stonehenge.
The henge is dated to the transition period between the neolithic and the Bronze age. Charred bones of many animals but largely pig were found in many of the holes. The neolithic monument Site Z is within the circle, and possibly another site, Z1. About 100 meters to the east is a cursus, a ceremonial causeway or walkway that probably dates to the same time as the pit circle.
There are four henges in the Boyne Valley dating to the late neolithic. One of the largest henges in the country, Site Q, is 1 kilometer east of Dowth. They are thought to belong to a time when many people were coming to visit the Boyne Valley: possibly neolithic pilgrims visiting in much the same way as happens at holy sites and shrines today.
The timber henge may have an astronomical purpose. A viewer standing on Site B on the flood plain below could watch midsummer sunsets and midwinter moonsets dropping between Sites K and L, Newgrange, and extreme moonsets through the timbers of the henge. A concern for studying the movements of the heavenly bodies in this region of the sky is found at Carrowkeel in County Sligo, in the chamber of Cairn G in particular.