The visitor centre at Donore, on the south bank of the Boyne, is the only way into Newgrange and Knowth. From here you cross the river on a footbridge and a shuttle bus takes your group to the tombs. The centre itself has an interactive exhibition on the Neolithic people who built the monuments, an audio-visual show and a wheelchair-accessible replica of the passage and chamber at Newgrange, which is the only way some visitors can see the interior.
Book tour tickets online through Heritage Ireland and only there; the Office of Public Works warns that tickets bought from other sites are not valid. Tickets are released 30 days ahead from April to early November and 7 days ahead in winter, and cancellations reappear at short notice. The centre has a café and a large car park. Bus Éireann route 163 runs from Drogheda, but check the timetable against your tour slot.