Now here's a thing: I couldn't get access to this as it's on the grounds of a chocolate factory! I was told by the security guard that I might get permission and be given a guided tour if I came back the following day, Monday.
Here's another thing: There is no mention of this in Tom Fourwind's book on prehistoric Dublin and I had never heard of it until reading Joseph E. Doyle's Ten Dozen Waters: The Rivers and Streams of County Dublin. Indeed, there it sits not 20 metres from the Santry river, just before it flows under the Malahide road. Doyle calls it a tumulus. It is mentioned on the Wikipedia page for the Santry river and it is on the archaeology.ie National Monuments database, number DU015-074-, added by Geraldine Stout no less.
So why isn't it more widely known? It's right there, less than a stone's (cough) throw from one of the busiest roads in the north suburbs.
When I first mentioned the Cadbury mound to my Auntie Bridie, she recounted a story from the 1950s about a man suffering a heart attack while felling one of the trees that grew upon it. This was attributed to the fairies taking retribution. More recently, I came across an account of a man who dug the 'fairy mound' and broke his leg. Another version of this tale tells of a strange face that appears under the branches of one of the trees at Hallowe'en and is thought to be that of a man who attempted to dig the mound and went missing that night. That these 'suburban myths' persist reveals much about local people's regard for the past.
From Michael Stanley's article 'Chocolate and Community Archaeology' in Archaeology Ireland (v25, no. 4, Winter 2011).
Description: Comprises a round -topped mound beside a stream in a low-lying location on the grounds of Cadbury's factory. The top has been planted with trees (diam. 19.20m, H 4.80m). (Morris 1939, 189; Dillon Cosgrave 1977, 110).
Compiled by: Geraldine Stout