Navan Fort (Old Irish: Emain Macha [ˈeβ̃ənʲ ˈβ̃axa]; Modern Irish: Eamhain Mhacha [ˌəunʲ ˈwaxə]) is an ancient ceremonial monument near Armagh, Northern Ireland. According to tradition it was one of the great royal sites of pre-Christian Gaelic Ireland and the capital of the Ulaidh. It is a large circular hilltop enclosure—marked by a bank and ditch—inside which is a circular mound and the remains of a ring barrow. Archeological investigations show that there were once buildings on the site, including a huge roundhouse-like structure that has been likened to a temple. In a ritual act, this timber structure was filled with stones, deliberately burnt down and then covered with earth to create the mound which stands today. It is believed that Navan was a pagan ceremonial site and was regarded as a sacred space. It features prominently in Irish mythology, especially in the tales of the Ulster Cycle. According to the Oxford Dictionary of Celtic Mythology, "the [Eamhain Mhacha] of myth and legend is a far grander and mysterious place than archeological excavation supports".
Navan Fort is the heart of the larger 'Navan complex', which also includes the ancient sites of Haughey's Fort (an earlier hilltop enclosure), the King's Stables (a manmade ritual pool) and Loughnashade (a natural lake that has yielded votive offerings).