Lugnaquilla[4] (Irish: Log na Coille, meaning 'hollow of the wood')[5] is the highest of the Wicklow Mountains in Ireland, rising to 925 metres (3,035 ft).

Joyce gave the original form as Log na Coilleach, which translates as "hollow of the (grouse) cocks", however, Tempan says that "this seems doubtful".

[5] The Geological Survey of Ireland ("GSI") describe Lugnaquilla as a "slate capped, granite rooted, relatively flat-topped mountain".

[11] Crags of dark-grey schist protrude from the upper cliff walls of Lugnaquilla's corries which are Ordovician in age.

[11] Cosmogenic dating on exposed bedrock showed that these schists were not covered by ice during the Last Glacial Maximum, and thus Lugnaquilla was a nunatak.

[11] Lugnaquilla is described as a "bulky mountain", with a large plateau-type grassy summit (known as Percy's Table), bounded on two sides by steep glacial corries called the "North Prison" (looking into the Glen of Imaal), and the "South Prison" (looking into the glen of the River Ow).