Knocknahillion (Irish: Cnoc na hUilleann, meaning "hill of the elbow")^[2] is one of the Maumturk Mountains of Connemara in County Galway, Ireland. At 607 metres (1,991 ft), it is the 210th–highest peak in Ireland on the Arderin list,^[3] and 256th–highest on the Vandeleur-Lynam list.^[4][5] Knocknahillion is in the middle sector of the long north-west to the south-east spine of the Maumturks.^[5][6] The summit is offset to the west of the rocky central ridge of the Maumturks, and its western-facing slopes have a distinctive "diagonal" rock stratification when viewed from the Inagh Valley.^[5][6]

Quick Facts Highest point, Elevation ...

Knocknahillion
Cnoc na hUilleann
Knocknahillion, viewed from Binn idir an dá Log; behind is the summit of Letterbreckaun
Highest point
Elevation	607 m (1,991 ft)[1]
Prominence	152 m (499 ft)[1]
Listing	Marilyn, Hewitt, Arderin, Simm, Vandeleur-Lynam
Coordinates	53°31′19″N 9°42′14″W[1]
Naming
English translation	hill of the elbow
Language of name	Irish
Geography
Knocknahillion Location in Ireland
Location	County Galway, Republic of Ireland
Parent range	Maumturks
OSI/OSNI grid	L8703653756
Topo map	OSi Discovery 37
Geology
Type of rock	Pale quartzites, grits, graphitic top bedrock[1]
Climbing
Easiest route	Via pass of Maumahoge

Close

Irish academic Paul Tempan notes that Knocknahillion derives its name from the townlands of Illion and Illion West (Irish: Uillinn, meaning "elbow").^[2][7] It is to the west of the central spine of the Maumturks range at a point where the range turns to a more south-easterly direction (like an elbow).^[6]

Knocknahillion is in the middle sector of the long north-west to south-east central spine of the Maumturks range in Connemara.^[6]

To the north, Knocknahillion is connected to Letterbreckaun, the 2nd highest peak in the range at 667 metres (2,188 ft), by a high winding rocky ridge that includes the subsidiary peak of Knocknahillion North Top at 541 metres (1,775 ft), whose prominence of 38 metres (125 ft) qualifies it as an Arderin.^[5] Further along this ridge lies the minor peak of Barrlugrevagh at 558 metres (1,831 ft), whose prominence of 17 metres (56 ft) qualifies it as an Arderin Beg.^[5]

To the southeast of Knocknahillion is the col of Maumahoge (Irish: Mhám Ochóige), which then rises up again to the corrie lake of Lough Maumahoge (Irish: Loch Mhám Ochóige), and eventually to Binn idir an dá Log, the highest mountain in the range at 702 metres (2,303 ft).^[5][6][8]

The easiest way summit Knocknahillion is a 5-kilometre 2-3-hour route via the pass of Maumahoge; however, because of its positioning on the high rocky central spine of the central Maumturk range, it is also summited in a longer 14-kilometre 5-6 hour loop-route starting at the col of Maumahoge in the south, climbing Knocknahillion and then along a winding 2-kilometre rocky ridge to the top of Letterbreckaun, before descending via the sharp "v-shaped" col of Maam Turk (Irish: Mám Tuirc, meaning "pass of the boar"), from which the entire range bears its name.^[6][8][9]

Knocknahillion is also climbed as part of the Maamturks Challenge, a 25-kilometre 10–12 hour walk over the full Maumturks range (from Maam Cross to Leenaun), which is considered one of the "great classic ridge-walks of Ireland",^[8] but of "extreme grade" due to the circa 7,600 feet of total ascent; however, because the peak of Knocknahillon is offset to the west of the core winding rocky ridge, it is not always summited during the challenge.^{[9][10][11][12]}

While the Maumturks range is not particularly known for rock climbing routes (unlike Bencorr and its Carrot Ridge spur, across the Inagh Valley), some have been developed at a crag just below and west of Lough Maumahoge (L876 532), with routes of 90 to 190 metres at climbing grades of S to HVS.^[13]

• Looking north to Letterbreckaun (left), and Knocknahillion (right), across Lough Inagh
• Lough Maumahoge, Knocknahillion (left) and the ridge to Letterbreckaun
• Letterbreckaun to Knockhillion ridge (middle, right), with Binn idir an dá Log (centre, back)
• Looking north to Knocknahillion (left), and Letterbreckaun (middle)
• Maumturks range from the Inagh Valley, with Knocknahillion (centre)

• Fairbairn, Helen (2014). Ireland's Best Walks: A Walking Guide. Collins Press. ISBN 978-1848892118.
• MountainViews Online Database (Simon Stewart) (2013). A Guide to Ireland's Mountain Summits: The Vandeleur-Lynams & the Arderins. Collins Books. ISBN 978-1-84889-164-7.
• Paul Phelan (2011). Connemara & Mayo - A Walking Guide: Mountain, Coastal & Island Walks. Collins Press. ISBN 978-1848891029.
• Dillion, Paddy (2001). Connemara: Collins Rambler's guide. Harper Collins. ISBN 978-0002201216.
• Dillion, Paddy (1993). The Mountains of Ireland: A Guide to Walking the Summits. Cicerone. ISBN 978-1852841102.

Wikimedia Commons has media related to Knocknahillion.

Wikimedia Commons has media related to Maumturk Mountains.

• Twelve Bens, major range in Connemara
• Mweelrea, major range in Killary Harbour
• Lists of mountains in Ireland
• Lists of mountains and hills in the British Isles
• List of Marilyns in the British Isles
• List of Hewitt mountains in England, Wales and Ireland