The Twelve Bens or Twelve Pins, also called the Benna Beola (), is a mountain range of mostly sharp-peaked quartzite summits and ridges in the Connemara National Park in County Galway, in the west of Ireland. The widest definition of the range includes the Garraun Complex to the north as well as several isolated peaks to the west, and is designated a Special Area of Conservation.
The highest point is Benbaun at . The range is a popular location for hill-walking activities with the 16–kilometre 8–9 hour Glencoaghan Horseshoe (Gleann Chóchan), considered one of the best ridge-walks in Ireland. Topographically, the range is partnered with the Maumturks range to the east of the Inagh valley (a Western Way route); and both share a common geology being largely composed of metamorphic marine rocks, being predominantly resistant quartzite but with deposits of schists in the valleys (known as Connemara Dalradian rocks).
Naming
"Ben" an anglicized translation of the Irish language word "Binn", meaning "peak". According to Irish academic Paul Tempan, "An odd thing about the Twelve Bens of Connemara is that nobody seems to know exactly which are the twelve peaks in question", and noting that there are almost 20 peaks with "Ben" or "Binn" in their name. Tempan notes that term "twelve peaks" can be at least dated to the Irish historian Ruaidhrí Ó Flaithbheartaigh, whose writings in 1684 said: "On the north-west of Ballynahinsy [Ballynahinch], are the twelve high mountaines of Bennabeola, called by marriners the twelve stakes [stacks], being the first land they discover as they come from the maine [sea]", but he did not list them.
The most common list of the twelve peaks in question are the peaks with an elevation above 500 metres in the core range, and that are not considered subsidiary peaks (e.g. they have a non-trivial prominence, and have been traditionally noted as peaks on historic maps, per below).
Tempan notes the issue of "twelve" does not arise in the Irish language name as they are simply labelled "Na Beanna Beola", which translates as "the peaks of Beola". Beola was a leader of the Fir Bolg, and a giant; his name appears in the Connemara village Toombeola, or Irish language "Tuaim Beola".
Geography
The Twelve Bens range is a core massif of 22 peaks above in elevation, centred around the highest peak in the range, Benbaun . To the north of this core massif lies the separate subsidiary massif of the Garraun Complex with 9 peaks around Garraun . To the west of the core massif lies 7 other isolated or subsidiary "outlier" peaks, thus giving a total of 38 Bens with an elevation above 100 metres.
While the Bens are not as high as those of the ranges in Kerry (e.g. MacGillycuddy's Reeks and the Mountains of the Dingle Peninsula), their rocky peaks and ridges contrast with the surrounding sea-level landscape (unlike Kerry, there are no mountain-passes in Connemara), and give the range an imposing feel.
The range is bounded by the Inagh Valley and the R344 road to the east, while the N59 road (or, the "Clifden Road"), circles and bounds the core massif (and most of the outliers), from the southerly, westerly and northerly directions. The Garraun Complex lies to the north of the N59 road at Kylemore Lough.
Core massif
The 22 peaks in the core massif of the Twelve Bens range naturally split into three sections:
The core massif is also known for its deep glaciated U-shaped valleys, around which groups of Bens lie in a "horseshoe formation":
Geology
The core massif of the Twelve Bens range are largely composed of metamorphic marine rocks, being predominantly resistant quartzite but with deposits of schists in the valleys (known as Connemara Dalradian rocks).
These rocks derive from sediments that were deposited in a warm shelf sea some 700 to 550 million years ago (e.g. Precambrian-Cambrian). Movements in the earth's crust, and the closure of the Iapetus Ocean, transformed these sediments into crystalline schists that lie underneath the base of the mountain range, which local erosion and uplift then brought to the surface. The summits of the core massif (and some outliers) are made of weather-resistant quartzite, while the sides of the peaks are composed of schists and grey marbles.
In contrast, the mountains to the north of the core Twelve Bens massif, the Garraun Complex, have a different type of geology, that is composed of gneiss and different forms of sandstones and mudstones.
Scattered throughout the range are parts of gabbro (Doughruagh and Currywongaun), mica schist (Muckanaght), and outcrops of marble (south of Kylemore Lough).