Lugnaquilla

Lugnaquilla (Irish: Log na Coille, meaning 'hollow of the wood') is the highest of the Wicklow Mountains in Ireland, rising to 925 metres (3,035 ft). It is also the highest Irish mountain outside of County Kerry, and the highest point in County Wicklow and the province of Leinster. Lugnaquilla overlooks the Glen of Imaal to the west and Glenmalure to the east.

Lugnaquilla is also the 11th-highest peak in Ireland on the Arderin list and 13th-highest on the Vandeleur-Lynam list.

Irish academic Paul Tempan wrote in his 2010 Irish Hill and Mountain Names, that the summit plateau is marked as Percy's Table, named after an 18th–century local landowner, Colonel Percy. This is similar to Dawson's Table on the summit of Galtymore. Tempan also notes that P.W. Joyce gave the original form as Log na Coilleach, which translates as "hollow of the (grouse) cocks", however, Tempan says that "this seems doubtful".

Tempan clarifies the name has no connection with the deity Lug, despite the common use of the term Lug as shorthand for Lugnaquilla, and that in some spellings of the name, several OS maps and guidebooks for example (e.g. Paddy Dillion's guidebooks), an "i" is added to give "Lugnaquillia"; however Tempan settles on "Lugnaquilla" as the proper name for the mountain.

The Geological Survey of Ireland ("GSI") describe Lugnaquilla as a "slate capped, granite rooted, relatively flat-topped mountain". Crags of dark-grey schist protrude from the upper cliff walls of Lugnaquilla's corries which are Ordovician in age. The protrusions of lighter grey rock are granite. The cap of schist overlying Lugnaquilla's granite core is the remnant roof of the magma chamber into which the Lugnaquilla granites were emplaced. 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, a summit or ridge protruding above an ice field or glacier.

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 (amphitheatre-shaped valleys) called the "North Prison" (looking into the Glen of Imaal), and the "South Prison" (looking into the glen of the River Ow). On Lugnaquilla's eastern side is the cliff-lined hanging valley of Fraughan Rock Glen, which falls into the glacial U-shaped valley of Glenmalure. The mountain is the source of the River Slaney.

Lugnaquilla does not have a rocky summit or summit ridges, and its large massif (principal mass) is described as a "sprawling mountain moorland". Its massif includes several major summits and corrie lakes, often lying in a "horseshoe-shape" with Lugnaquilla at the apex around deep valleys. Around the Fraughan Rock Glen and Arts Lough in the east are Benleagh and Clohernagh peaks; around the glen of the Carrawaystick River and Kelly's Lough in the southeast are Corrigasleggaun peak and, again, Clohernagh peak; around the glen of the River Ow in the south are Corrigasleggaun and Slievemaan peaks; and finally, around the larger Glen of Imaal in the west are Ballineddan Mountain, Slievemaan, Camenabologue, Table Mountain, Lobawn, and Sugarloaf peaks.

Lugnaquilla is the highest mountain of the Wicklow Mountains range, and the highest mountain in Ireland outside County Kerry. Its large prominence qualifies it to meet the P600 classification (mountains known as the "Majors" in Britain and Ireland), and the Britain and Ireland Marilyn classification. It is the fourth-highest mountain in the MountainViews Online Database, 100 Highest Irish Mountains.