Side plan of the passage and chamber of Newgrange

31 The stone passage, chamber and corbelled roof of Newgrange, and the kerb of 97 stones, were constructed without the use of mortar.

32 The total length of the passage and chamber together is 24m (79ft), which means they only occupy one third the diameter of the mound.

33 In the passage, there are 22 orthostats or standing stones on the left (Western) side and 21 on the right (east). They have an average height of 1.5m, with the tallest stones nearer the chamber.

34 A total of 17 roof slabs can be seen covering the passage.

35 The large slab which can be seen pinned to the wall outside the passage mouth may have originally been used by the builders to block the passage when construction of the cairn was complete.

36 There are three separate chambers, or recesses, off the central chamber. The eastern chamber is the most impressively decorated, although all three contain decoration.

The corbelled chamber ceiling

37 The corbelled roof of the chamber is one of the finest of its kind in Europe, and when Newgrange was excavated it was found to be standing intact without any repair work exactly as it had done when first built.

38 At one time, there was what was described as a "pyramidal-shaped" stone in the centre of the chamber. Some time after it was recorded by Thomas Molyneaux, it disappeared and has not been seen since.

39 All of the orthostats (standing stones) in the chamber are used to support the corbelled roof. Some have leaned inwards over time due to the weight of the cairn material pressing down on the chamber.

40 The tomb builders filled the gaps between the roof stones in the passage with sea sand and burned soil to keep the passage dry.