Anta is the Portuguese name for about 5,000 megaliths built during the Neolithic period in the area of Portugal. The Anta das Pedras Grandes is a late-Neolithic site located in Casal Nova in the parish of Caneças, in the Odivelas municipality, in the Lisbon District of Portugal. It was classified as a National Monument in 1944. Excavations in the early 21st century suggest that it was originally built as a dolmen or single-chamber megalithic tomb, consisting of a polygonal long chamber with eight supporting stones about 3 metres tall, and a short access corridor. There are traces of a tumulus, and human bones have been discovered. Excavations in the surrounding area also identified many flint chippings, suggesting that the area was used for the production of flint items.