Dowth is another passage tomb constructed during the same period as Knowth and Newgrange. Knowth, Dowth, and Newgrange comprise the three primary megalithic passage tombs of the Brú na Bóinne World Heritage Site. Dowth is more than 5000 years old and measures approximately 15m in height and 85m in diameter. The passage tomb was constructed using large and impressively decorated kerbstones. There are two tombs on the western side and a 14m passage that ends with a cruciform chamber. There is a crater in the middle of the mound as a result of an unprofessional excavation in 1847.

Similar to Newgrange, Dowth displays an amazing sight during the Winter Solstice. From November to February, during the evening hours, sunrays enter the passage and the chamber of the monument. The sunrays move alongside the left of the passage and enter the circular chamber. This is where the rays illuminate three stones. There is a central stone, which is convex, that reflects the rays into a dark recess. This process illuminates all of the the decorated stones. After a few hours, the rays move back slowly alongside the right of the passage and exit the chamber. This would be an astonishing feat to witness; however Dowth, unlike Knowth and Newgrange, has not been renovated and is not accessible to the public.