Knowth (/ˈnaʊθ/; Irish: Cnoghbha) is a Neolithic passage grave and an ancient monument of Brú na Bóinne in Ireland's valley of the River Boyne. It is the largest passage grave of the Brú na Bóinne complex and consists of a large mound (known as Site 1) and 17 smaller satellite tombs. The mound is about 12 metres (40 ft) high and 67 metres (220 ft) in diameter,[1] covering roughly a hectare. It contains two passages placed along an east-west line and is encircled by 127 kerbstones, of which three are missing, and four badly damaged.