The Twelve Bens or Twelve Pins, also called the Benna Beola (), is a mountain range of mostly sharp-peaked quartzite summits and ridges in 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. in 2010, Tempan wrote the Irish Hill and Mountain Names, collating the accepted names (e.g from academic research, the Placenames Database of Ireland (loganim.ie), and the Ordnance Survey Ireland) for Irish mountains from the MountainViews database, and which he updated in 2012. 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 core massif is also known for its deep glaciated U-shaped valleys, around which groups of Bens lie in a "horseshoe formation":
These rocks derive from sediments that were deposited in a warm shelf sea some 700 to 550 million years ago (e.g. Precambrian-Cambrian).
The 8–9 hour Glencoaghan Horseshoe 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.
An even more serious undertaking is the "Twelve Bens Challenge", climbing all 12 Bens in a single 24-hour day.
Rock climbing
thumb|upright=1.2|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"). 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 (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 Log an Choire Bhig, ("wood of the small corrie"), has a number of shorter but harder climbs including "Corner Climb" (VS 4c, 30 m).
List of peaks
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
The list below highlights the 12 Bens most associated with being the Twelve Bens from Ó Flaithbheartaigh's original record.