[6] It was once believed that these features were man-made: for instance, Gabriel Beranger wrote of them in 1780, "I take them to be altars upon which sacrifices were offered […] the regularity which is observed in piling them convinces me they are the work of man, as they could not grow in that position".

[9] The writer Weston St. John Joyce described the vista thus: "The view from this commanding height, 1,479 feet over sea-level, extends over a vast tract of mountain, sea, and plain, comprising, to the north, the blue waters of Dublin Bay, with Clontarf and Howth, the Naul or Man-of-War hills, and the Mourne Mountains; eastward, Kingstown, Dalkey, and Killiney, and then in succession the fertile vale of Shanganagh, Carrickgollogan, the Scalp, Bray Head, the Sugar Loaves, and the slopes of Prince William's Seat.

In clear weather Holyhead and the Welsh mountains may frequently be discerned, Snowdon and the Llanberis Pass being usually the most conspicuous, but occasionally the elongated outline of Cader Idris may be observed some distance to the right".

[2] In 2007 a concept was submitted to Dún Laoghaire–Rathdown County Council to create a cableway from the Sandyford Luas stop to Three Rock Mountain and to open up the views to touristic and easier access.

[18][19] During the nineteenth century, much of the lower slopes of Three Rock were covered with small quarries, especially around the village of Barnacullia, which supplied paving stones for Dublin Corporation for many years.

[23] The main transmission site on Three Rock is owned and operated by 2RN a subsidiary of the Irish national broadcaster RTÉ, its 140-metre (360') cable-stayed mast is close to the peak, which is 448 metres (1470') above Ordnance Datum.

Today the Three Rock transmitters provide the Irish digital television service, Saorview, to Dublin city and county,[24] as well as FM and DAB radio networks.