Newgrange (Irish: Sí an Bhrú) is a prehistoric monument located in County Meath, on the eastern side of Ireland, about one kilometre north of the River Boyne. It was built between circa 3100 and 2900 BC, during the Neolithic period. There is no agreement about what the site was used for, but it has been speculated that it had some form of religious significance because it is aligned with the rising sun on the winter solstice, which floods the stone room with light. It is in fact just one monument within the Neolithic Brú na Bóinne complex, alongside the similar passage tomb mounds of Knowth and Dowth, and as such is a part of the Brú na Bóinne UNESCO World Heritage Site. Newgrange also shares many similarities with other Neolithic constructions around Western Europe, such Maeshowe tomb in Orkney, Scotland and the Bryn Celli Ddu site in Wales.
After its initial use, the entrance to Newgrange was sealed and it remained closed for several millennia, subsequently gaining several associations in local folklore and mythology. It first began to be studied as a prehistoric monument by antiquarians in the seventeenth century AD, and over subsequent centuries various archaeological excavations took place at the site before it was largely restored to an interpretation of its original Neolithic appearance by conservators in the 1970s. Today, Newgrange is a popular tourist site, and according to the archaeologist Colin Renfrew, is "unhesitatingly regarded by the prehistorian as the great national monument of Ireland" and is also widely recognised as one of the most important megalithic structures in Europe.