This ancient fortification covers roughly 2.9 hectares and features a distinctive double rampart system that encircles the entire site. What makes Rathcannon particularly intriguing is the unusual spacing between its two defensive rings; they're separated by anything from 23 to 200 metres, with the outer rampart cleverly following the natural contours of the limestone plateau rather than maintaining a uniform distance.

The hillfort takes on a somewhat oval shape, and whilst archaeologists haven't identified any obvious entrance points, the defensive earthworks remain clearly visible today. The inner rampart appears on historical Ordnance Survey maps dating back to the first and second editions, suggesting it was still a prominent landscape feature when those early surveys were conducted. Surface examinations haven't revealed any internal structures or features, though this doesn't mean they don't exist; many such sites require excavation to reveal their secrets.

Recent archaeological assessments, including its inclusion in the Atlas of Hillforts of Britain and Ireland, have helped document this important Iron Age monument. Tom Condit produced a basic site plan in 1995, whilst Eoin Grogan's 2005 survey work has added to our understanding of the fortification's layout and construction. Like many Irish hillforts, Rathcannon likely served multiple purposes; defensive stronghold, ceremonial centre, and symbol of power for the community that built and maintained it over two millennia ago.