Caerau Hillfort is a large triangular multivallate Iron Age hillfort, built on a previously occupied Neolithic site, occupying the western tip of an extensive ridge-top plateau in the western suburbs of Caerau and Ely, Cardiff, Wales. It is the largest Iron Age site of its type in south Wales and also one of the largest in Great Britain. The old parish church, St Mary's, and a small ringwork, almost certainly a medieval castle site probably contemporary with the church, stand within the hillfort on the north-eastern side.The hillfortCaerau Hillfort is the third largest Iron Age hillfort in Glamorgan, enclosing 51,000 m², and is surrounded by housing and the A4232. It was once a stronghold of the powerful Silurian tribe who inhabited this part of Wales before the arrival of the Romans.Although excavations during Channel 4's Time Team series in April 2012 showed the hillfort's occupation began about 2550 years before present (BP), further excavations in 2013–2014 revealed evidence of the site's occupation back to the early Neolithic. Finds included flint tools and weapons dating to 5550 BP. Iron Age and Romano-British pottery as well as a single fragment of a mortarium (1st century AD Roman pouring vessel) have been found from an area north-west of the southern entrance.