It measures roughly 12.4 metres long, 11.5 metres wide, and rises to about 1.5 metres in height, with an opening of around 9 metres facing south-east. This is a fulacht fia, a type of ancient cooking site found in great numbers across Ireland, particularly from the Bronze Age onwards. The characteristic horseshoe or kidney shape comes from the gradual accumulation of discarded burnt stone: rocks would be heated in a fire, dropped into a water-filled trough to bring it to the boil, and then raked aside once spent. Over generations of repeated use, that debris builds into exactly the kind of mound visible here.

The site at Carhoo is not alone in its immediate surroundings. A second possible fulacht fia has been recorded approximately 30 metres to the north-west, suggesting this stretch of ground may have seen repeated or prolonged activity rather than a single, isolated episode of use. The pairing of fulachtaí fia in close proximity is not uncommon in the Irish archaeological record, though the reasons remain debated. Some researchers associate them with hunting camps, others with communal gatherings, and more recent scholarship has raised the possibility of uses beyond simple cooking, including textile processing or bathing. What is clear is that sites like this one were functional, well-used places, and the sheer volume of accumulated burnt stone at Carhoo points to sustained activity over time.