On the south side of the mountain, in the townland of Knockalassa, are the remains of two megalithic tombs; one on the mountainside and one further down by the Ennis Road.

Charles Vallancey and Theophilus O'Flanagan published what they claimed was a poem from the medieval tale Cath Gabhra, which says that Conán was slain at Slievecallan during a ceremony to worship the sun.

[1] The mountain sits more or less in the centre of the triangle formed by the villages of Milltown Malbay, Inagh and Connolly, in the west of County Clare.

The forestry is mainly plantations of Sitka spruce (Picea sitchensis)[10] A wind farm on Slievecallan, with accompanying roads and substations, was approved planning permission in 2017 – despite opposition from locals and An Taisce (The National Trust).

[13][14] Completed in 2018, the wind farm was sold in 2020 by the then owners (WCRE Windfarms Ltd and Brookfield Renewable Partners) to a joint venture comprising Japan's Mitsubishi UFJ Lease & Finance Co and Arjun Alliance UK 2 LP.