This remarkable circular enclosure consists of four concentric ramparts that stretch across 7.3 hectares on the western edge of a prominent ridge, with the outermost rampart reaching an impressive diameter of 320 metres. The site overlooks the tributary of the Derreen River and has been protected under a preservation order since 1940.

The hillfort's history spans from the Late Bronze Age through to the Early Medieval period, creating a fascinating archaeological palimpsest. At its heart lies a well-preserved medieval stone enclosure, approximately 45 metres in diameter, defined by a massive four-metre-wide drystone rampart. This central ringfort is surrounded by two closely spaced stone ramparts dating to the Late Bronze Age, which rise to about five metres in height. The outermost earthen rampart, positioned 50 metres further out, completes this extraordinary defensive system, though parts now survive only as field boundaries.

Excavations by Barry Raftery in the late 1960s and early 1970s revealed the site's true significance as a major Late Bronze Age settlement and metalworking centre. Within the central enclosure, archaeologists uncovered evidence of bronze manufacturing, including thousands of pottery sherds, six hearths, numerous pits and post-holes, and even four human burials. The discovery of over 5,000 sherds of coarse pottery and extensive metalworking debris suggests this was a thriving industrial and residential complex. Recent research has identified 47 radiocarbon dates from the Late Bronze Age alone, making Rathgall one of the most thoroughly dated prehistoric sites in Ireland.