List of mountains in the Republic of Ireland

In these lists of mountains in Ireland, those within Northern Ireland, or on the Republic of Ireland – United Kingdom border, are marked with an asterisk, while the rest are within the Republic of Ireland. Where mountains are ranked by height, the definition of the topographical prominence used to classify the mountain (e.g. the change in elevation required between neighbouring mountains), is noted. In British definitions, a height of is required for a mountain, whereas in Ireland, a lower threshold of is sometimes advocated.

The lowest minimum prominence threshold of any definition of an Irish mountain is (e.g. the Vandeleur-Lynam), however most definitions, including the International Climbing and Mountaineering Federation (UIAA) criteria, do not consider prominences below as being mountains (e.g. must at least be an Arderin or a Hewitt). Many British definitions consider a peak with a prominence below , as being a ''top'', and not a mountain (e.g. must be a Marilyn). A widely used definition of an Irish mountain requires a minimum prominence of (e.g. a HuMP), and is the basis for the ''100 Highest Irish Mountains''.

While Irish mountains are ranked according to Irish classifications, they are also ranked on classifications that cover Britain and Ireland (e.g. Simms and P600s).

Definitions

General concepts

There is no consensus on the definition of "mountain", but in Britain and Ireland it is often taken to be a summit over 2,000 ft, or more latterly, 600 m.''A Mountain is a Mountain – isn't it?''
at www.go4awalk.com. Accessed on 3 Feb 2013. There is less consensus about the topographical prominence requirement (e.g. the change in elevation required between neighbouring mountains), which can vary between . Prominence is even strongly debated regarding UIAA classification of Himalayan mountains. In the alps, the UIAA requires a prominence of over 30 m to be a "peak" and over 300 m to be a "mountain".

The lowest threshold of prominence in Britain and Ireland is . The only definition in which prominence is not used, is where topographic isolation is used (e.g. the use of "sufficient separation" for Munros). Most Britain and Ireland definitions no longer categorise prominences below (e.g. no new Nuttalls and Vandeleur-Lynams), and peaks with a prominence between are now defined as tops rather than mountains (e.g. the 227 Munro Tops).

In Ireland, a prominence threshold of is proposed for a mountain.

Main classifications

Other classifications

The term Dillon is used to describe any of the 212 Irish summits in Paddy Dillon's well–regarded Irish 2010 climbing guidebook: "The Mountains of Ireland". All of Dillon's summits are over , and almost all have a prominence above (i.e. they are very similar to the list of 209 Irish Hewitts).

The term Myrddyn Deweys are peaks in Ireland, between 500 metres to in height, with a prominence above , which was published by Michael Dewey and Myrddyn Phillips in 2000. Myrddyn Deweys are the Irish equivalent of Deweys, which extend the Hewitt classification down to 500 metres. There are 200 Myrddyn Deweys.

''MountainViews Online Database''

MountainViews was created in 2002 by Simon Stewart as a non–profit online database for climbers in Ireland to document and catalogue their Irish climbs. Its main data source are from the Ordnance Survey Ireland (OSI) maps, although it also conducts its own surveys, which the OSI has integrated into its own database, and it also integrates other important Irish mountain databases such as the Paul Tempan's work with the Placenames Database of Ireland (Loganim). Collins Press published the MountainView Online Datase in 2013 in the book: ''A Guide to Ireland's Mountain Summits: The Vandeleur-Lynams & the Arderins''.

Since 2012, MountainViews has been partnered with the ''Database of British and Irish Hills'' (DoBIH), which is the main live database for the categorisation of mountains and hills in Britain and Ireland. However, MountainViews can differ slightly from DoBIH on the measurements for certain Irish mountains.

List of the 10 Highest MacGillycuddy's Reeks

The MacGillycuddy's Reeks range contains Ireland's highest mountain, Carrauntoohil , and the Reeks is the highest range of peaks in Ireland. However, many of its peaks do not meet all classification criteria for a "mountain" (e.g. particularly the in elevation change from neighboring mountains), and many are not in the ''100 Highest Irish Mountains''. Regardless, the range contains ten of the thirteen Scottish Furths in Ireland, and given its importance, and as an important example of complexity of mountain classification, the ten highest Reeks are listed below:

''100 Highest Irish Mountains''

(any height, prominence over 100 m)

This is the MountainViews ''100 Highest Irish Mountains'' list, which was published by Collins Press in the 2013 book: ''A Guide to Ireland's Mountain Summits: The Vandeleur-Lynams & the Arderins''. It combines Paul Tempan's 2012 research into Irish mountains and Irish mountain names. The list requires a prominence of over , a compromise between the popular British Isles Marilyn criteria of 150 metres (see List of Marilyns in the British Isles for a ranking of Irish Marilyns by height and by prominence), and the Simms–Hewitt–Arderins criteria of 30 metres (see List of mountains of the British Isles by height for a ranking of Irish Simms by height and by prominence). It is a widely used list, and it contains 25 of the 26 Irish P600s (Slieve Snaght, a P600, did not make the 100 Highest).

List of ''406 Irish Arderins''

(height above 500 m, prominence over 30 m)

A noted definition of an Irish mountain over the lower height threshold of , is the Arderins list, but which meets the minimum requirement for a "mountain" with a prominence above , and is an Irish equivalent of the Hewitt (the 207 Arderins over are the 207–209 Irish Hewitts), or the Simm (the 222 Arderins over are the 222–224 Irish Simms). The 199 Arderins below are the Myrddyn Deweys (e.g. the total of the 207 Irish Hewitts and the 199 Myrddyn Deweys equal the 406 Irish Arderins).

MountainView's Online Database of Arderins was published by Collins Press in the 2013 book: ''A Guide to Ireland's Mountain Summits: The Vandeleur-Lynams & the Arderins'', and updated in 2015. In 2018, the MountainView Online Database listed 406 Irish mountains as meeting the Arderin definition. , nobody is officially recorded as climbing all the Irish Arderins.

MountainViews uses the term Arderin Begs for the additional class of peaks over in height, and with a prominence between . In 2018, Ireland had 124 Arderin Begs.

List of ''273 Irish Vandeleur-Lynams''

(height above 600 m, prominence over 15 m)

The broadest noted definition of an Irish mountain over is the Vandeleur-Lynam list, as it only requires a prominence of , and is the Irish fully metric equivalent of the England & Wales Nuttall. The ''100 Highest Irish Mountains'' from above, is a ''subset'' of this list (e.g. they are all Vandeleur-Lynams). For example, Mweelrea, the highest mountain in Connacht, is 16th on the ''100 Highest Irish Mountains'' list, but 34th on the Vandeleur-Lynam list. MountainView's Online Database of Vandeleur-Lynams was published by Collins Press in the 2013 book: ''A Guide to Ireland's Mountain Summits: The Vandeleur-Lynams & the Arderins'', and updated in 2015. In 2018, the MountainView Online Database listed 273 Irish mountains as meeting the Vandeleur-Lynam definition.

On 3 October 2018, English Lake District climber, James Forrest, completed all 273 Irish Vandeleur-Lynams in 8 weeks.

Lists of Irish hills

Carns

MountainViews and Database of British and Irish Hills recognise a list of 337 summits as Carns, having height above and below .

Binnions

MountainViews and Database of British and Irish Hills recognise a list of 484 summits as Binnions, having prominence at least and height below .

List of Irish County and Provincial Tops

Provincial Tops

There are 4 Irish Provincial Tops, namely: Carrauntoohil, in Munster, Lugnaquilla