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). The highest point is Benbaun at 729 metres (2,392 ft). The range is a popular location for hill-walking activities with the 16–kilometre 8–9 hour Glencoaghan Horseshoe (Irish: Gleann Chóchan), considered one of the best ridge-walks in Ireland.
"Ben" an anglicized translation of the Irish language word "Binn", meaning "peak". According to Irish academic Paul Tempan,[e] "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 a 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 § List of peaks 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".
Glencoaghan River from Bencullaghduff
The Twelve Bens range is a core massif of 22 peaks above 100 metres in elevation, centred around the highest peak in the range, Benbaun 729 metres (2,392 ft). To the north of this core massif lies the separate subsidiary massif of the Garraun Complex with 9 peaks around Garraun 598 metres (1,962 ft). 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.
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.
The 22 peaks in the core massif of the Twelve Bens range naturally split into three sections:
Southern Bens, 12 southern Bens form a horseshoe around the Glencoaghan Valley, and include the 7 major Bens of: Derryclare, Bencorr, Bencollaghduff, Benbreen, Bengower, Benlettery, and Benglenisky; and 5 subsidiary Bens of: Bencorr North Top, Benbreen Central Top, Benbreen North Top, Binn an tSaighdiúra, and Bencorrbeg; and
Central Bens, 7 central Bens that sit along a large east-west ridge with Benbaun at its centre, and include the 4 major Bens of Benbaun, Benfree, Muckanaght, and Bencullagh; and the 3 subsidiary Bens of Knockpasheemore, Maumonght, and Maumonght SW Top; and
Northern Bens, 3 northern Bens that lies on the small massif of the major Ben of Benbrack, and include the 2 subsidiary Bens of Knockbrack and another smaller peak called, Benbaun; just beside the Northern Bens lies the outlier Ben of Diamond Hill.
The core massif is also known for its deep glaciated U-shaped valleys, around which groups of Bens lie in a "horseshoe formation":
Glencoaghan: most southerly valley from which the Glencoaghan river flows; the Glencoaghan Horseshoe is a major hill-walking route in Ireland;
Owenglin: western valley from which the Owenglin river flows; the Owenglin Horseshoe is also a noted hill-walking route;
Gleninagh: eastern valley from which the Gleninagh river flows; contains Carrot Ridge, an important area for rock-climbing;
Polladirk: north-westerly valley from which the Polladirk river flows; a popular scenic view from Diamond Hill is into this valley;
Glencorbet: north-easterly valley from which the Kylemore river flows; the Glencorbet Horseshoe is a popular route in the Bens.
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.
The Irish Times outdoors correspondent, John G. Dwyer, said of the Twelve Bens, "These are true kickass mountains, with criminally stunning views [..]".
The 16–kilometre 8–9 hour Glencoaghan Horseshoe (Irish: Gleann Chóchan)[b] is noted as providing some of the "most exhilarating mountaineering in Ireland", and is called "a true classic" by guidebook authors. Other similar distanced "horseshoe" loop walks are the 19–kilometre 10–12 hour Owenglin Horseshoe, the 15–kilometre 8–9 hour Gleninagh Horseshoe, and the 14–kilometre 6–7 hour Glencorbet Horseshoe.
However, an even more serious undertaking is the 28–kilometre Twelve Bens Challenge, climbing all 12 Bens in a single 24-hour day.[c]
Carrot Ridge in the Gleninagh Valley
The Twelve Bens have a number of rock climbing locations, the most notable of which is in the Gleann Eighneach valley at the eastern spur of Benncorr (from Binn an tSaighdiúra to Bencorrbeg; also called "Carrot Ridge" Irish: Meacan Buí). The climbs vary from Diff (D) to Very Severe (VS) and range from 150 metres to 320 metres in length, with notable routes being Carrot Ridge (275m D), and Seventh Heaven (330m HS).
In addition, the large easterly corrie between the summits of Derryclare and the summit of Bencorr, known as Irish: Log an Choire Mhóir (meaning "wood of the big corrie"), also contains several large 200 metre multi-pitch graded rock climbs at grades of Diff (D) to Very Diff (VD), the most notable of which is The Knave (VD, 225 m); and the smaller corrie between the summit of Bencorr and the summit of Bencorr North Top, known as Irish: Log an Choire Bhig (meaning "wood of the small corrie"), has a number of shorter but harder climbs including Corner Climb (VS 4c, 30 m).
The following is a download from the MountainViews Online Database, who list 38 identifiable peaks in the wider Twelve Bens range (i.e. core massif, Garraun complex, and various outliers to the west), with an elevation, or height, above 100 metres (328 ft)
The list below highlights the 12 Bens most associated with being the Twelve Bens from Ó Flaithbheartaigh's original record. Of the standalone "Bens" (e.g. not listed as a "Top" of a parent Ben) that are over 500 metres (1,640 ft) in height but are not listed in this 12, Binn an tSaighdiúra has a prominence of only 8 metres and would not qualify as an independent mountain on any recognised scale (the lowest prominence is 15 metres for the Vandeleur-Lynam classification); Maumonght does have a prominence exceeding 50 metres, and even has a subsidiary peak (Maumonght SW Top), however, Maumonght rarely appears on historic maps of the range and is not considered a "Ben"; Bencorrbeag also has a non-trivial prominence of 42 metres, however, it is considered unlikely given its positioning that it could have been distinguished by mariners from the sea (Ó Flaithbheartaigh's original premise).
One of the original Twelve Bens; equated to all non-subsidary peaks in the core massif with height above 500 metres (1,640 ft)
Marilyn: Any height, and prominence over 150 metres (492 ft).
^ abcThe translation is "the peaks of Beola" who was believed to be a giant and chieftain of the Fir Bolg, whose name features in the village Tuaim Beola (Toombeola).
^ abAlso known as the "Derryclare Horseshoe" as it is normally started from the Derryclare end (e.g. counterclockwise), is a 14 to 16 kilometre "horseshoe"-shaped circuit (the final length depending on whether the "loop" is completed by walking back to the base of "Derryclare"), that takes in six of the twelve bens, almost 5,000 ft of elevation, and takes circa 6 to 9 hours to complete depending on ability and fitness.
^ abThe "12 Bens Challenge" was organised by the Beanna Beola Hillwalking Club on a yearly basis since 2006; it is for advanced hill-walkers only, and covers 28 kilometres, 8,300 ft of elevation, and takes circa 12–14 hours to complete.
^Only part of the range is inside the boundary of the Connemara National Park; the rest is on private property, but climbing access is granted.
^The name is assumed to derive from the abundance of white quartzite rock on its summit
^Cartographer and climbing author Tim Robinson gave an alternative name of Irish: Binn an Choire Mhóir meaning "peak of the big corrie". The British sappers set up a beacon on this peak during the first Ordnance Survey in Ireland.
^The "black hags" are not referring to witches, but to cormorant birds.
^Braon in the Irish language can mean "drip" or "drop", but is more likely related to the Irish personal name, and it is the basis of the surnames Ó Braoin and Mac Braoin, anglicised as Breen and McBreen in the area.
^The Irish language term "clár", can mean both a "plain" and a "board"/"plank-bridge". Thus Derryclare, from "Doire Chláir", could mean 'oak-wood of the plain' or 'oak-wood of the plank-bridge'. The name seems to have been transferred by the Ordnance Survey from the townland of Derryclare situated to the east to the mountain itself.
^Mistakenly marked as "Glengower" on the Discovery series OS map.
^It is said that a British sapper from the first Ordnance Survey in Ireland fell to his death here during survey work on the first 6-map series in the 1830s.
^On the Discovery OS map this peak is marked as "Luggatarriff", meaning "hollow of the bull", which Paul Tempan notes probably applies to a hollow on the slopes of Benfree.
^A woman known as "Cailleach an Chlocháin", meaning "the witch of Clifden", was a famous character in the 19th-century.
^Despite is non-trivial prominence, Maumonght is unnamed on many maps, including Tim Robinson's map, however, a lower peak to the SW at 454 metres, is named Binn Bhreac (properly Maumonght SW Top). This may explain why Maumonght rarely appears in any list of the actual 12 Bens. "Maumonght" is also odd as an anglicised form, as Paul Tempan notes that it does not suggest any Irish version, and wonders if it was a typo for "Maumought".
^Paul Tempan notes that Garraun is clearly also a name of Irish origin, and may either be from the Irish name "garrán" (meaning grove), or, more likely, from the Irish name "géarán" (meaning "fang"). While the summit of Garraun is flattish, the eastern ridge leading to it is sharp enough to have deserved the name of "fang". Tempan notes that the name "Maolchnoc" could be the true Irish name for the rounded summit, while "An Géarán" would denote the sharp ridge descending to Lough Fee.
^The summit of this mountain is strewn with lumps of white quartz.
^Cuanna is probably a personal name. A townland nearby is named Tooreenacoona ("Tuairín Uí Chuanna", meaning "O'Cooney's Green").
^The townland of Lettery (Irish: Leitrí, "wet hillsides") is on the southerly slopes of the peak. Another name Bindowglass or Bendouglas (Irish: Binn Dúghlais, "peak of the black stream") is recorded as early as 1684 by Ruaidhrí Ó Flaithbheartaigh; both names referring to the wet state of the peak. Ó Flaithbheartaigh mentions a pool of water on the summit which turns the hair white of anyone who washes in it.
^ abcdefHelen Fairbairn (30 December 2014). Ireland's Best Walks: A Walking Guide (Walking Guides). Collins Press. ISBN978-1848892118. ROUTE 34: The Glencoaghan Horseshoe. A true classic
^ abPaul Tempan (2006). "Two Mountain Names: Slieve Felim and Mauherslieve"(PDF). North Munster Antiquarian Journal. 6: 121. The formula is preserved in the range known in English as "The Twelve Bens of Connemara", although the names of the exact twelve peaks are no longer known
^"About Us". Placenamesni.org. Retrieved 13 March 2020.
^ abLynam, Joss; Robinson, Tim (1988). Mountains of Connemara: Hill Walker's Guide. Folding Landscape. ISBN978-0950400242.
^ abPaul Phelan (2011). Connemara & Mayo - A Walking Guide: Mountain, Coastal & Island Walks. Collins Press. ISBN978-1848891029. Route 12: Glencoaghan Horseshoe. one of Ireland's most dramatic walks
^ ab"Glenn Eighneach". Irish Climbing Wiki. The finest rock formations in the Twelve Bens are found in the south wall of Gleann Eidheanach (Glen Inagh), running from Binn an Choire Bhig to Mám na bFhonsaí, east of Binn Dubh (L808530).
^"12 Bens Challenge". Na Beanna Beola Hill Walking Club. 2018. The route begins at the Inagh Valley Inn and ends at the Bard’s Den in Letterfrack. The total distance covered is approximately 28km and the total height gain for the route is approximately 2530m (8300ft). On average it takes 12–14 hours to complete and should only be attempted by competent hill-walkers.