Maes Howe is a Neolithic chambered cairn and passage grave situated on Mainland Orkney (off northern Scotland). The monuments around Maes Howe, including Skara Brae, were designated a UNESCO World Heritage Site in 1999. It gives its name to the Maes Howe Type of chambered cairn, which bears no similarities to any other known chambered cairn design, either in Orkney or elsewhere.

Built originally by the Grooved Ware People, the site is close to several other significant ancient monuments thought to be contemporary with Maes Howe.

It was looted by Vikings (possibly Earl Rognvald) in c. 12th century AD, who left, in their passing, a series of runic graffiti on the central supporting stones of the chamber while they sheltered. It is the longest runic inscription known so far.

The corbelled roof was shattered in 1861 by overenthusiastic "archaeologists". Luckily, they did relatively little structural damage and the site still represents a standard of exacting design and construction not found anywhere else in Britain.

See also: Ring of Brodgar