The circular mound at Dowth is similar in size to Newgrange – about 63m in diameter – but is slightly taller at 14m high. It has suffered badly at the hands of everyone from road builders and treasure hunters to amateur archaeologists, who scooped out the centre of the tumulus in the 19th century. For a time, Dowth even had a tearoom ignobly perched on its summit. Because it's unsafe, Dowth is closed to visitors, though the mound can be viewed from the road between Newgrange and Drogheda. Serious excavations began in 1998 and will continue for years to come.
Dowth has two entrance passages leading to separate chambers (both sealed), and a 24m early-Christian underground passage at either end, which connect with the western passage. This 8m-long passage leads into a small cruciform chamber, in which a recess acts as an entrance to an additional series of small compartments, a feature unique to Dowth. To the southwest is the entrance to a shorter passage and smaller chamber.
North of the tumulus are the ruins of Dowth Castle and Dowth House .