The Anta de Adrenunes, located on top of a hill at 426 metres above sea level, in the municipality of Sintra, within Sintra-Cascais Natural Park, Lisbon District, Portugal, is believed to be a Stone Age burial chamber or megalithic monument.

The passage is thought to have served as a collective necropolis or dolmen during the megalithic period although no artifacts or burial chambers have been found to prove this.

However, Da Silva presented the results of his research at one of the sessions of the International Congress of Anthropology and Prehistoric Archeology in 1871, referring to the site as a megalithic funerary monument.

Later writers have argued that the site combines natural granite rocks, which are also found elsewhere in the area, with some architectural elements.

They point to the layout of the rocks and their orientation to the sunset to argue that this suggests a megalithic structure that was probably of natural origin and was later worked on by humans.