Lists of mountains in Ireland

thumb|right|250px|A topographic map 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 Great Britain and Ireland (e.g. Simms and P600s).

Definitions

General concepts

thumb|upright=1.6|[[Mweelrea from Doo Lough in Connemara. Mweelrea is the provincial top of Connacht, the county top of Mayo, the 5th highest Irish P600 mountain, the 14th highest Irish Marilyn mountain, the 16th highest Irish MountainViews mountain, the 26th highest Irish Arderin/Hewitt mountain, and the 34th highest Irish Vandeleur-Lynam/Nuttall mountain. It is not a Furth (or Irish Munro), and therefore not a Real Munro.]]

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. There is less consensus about the topographical prominence requirement (e.g. the change in elevation required between neighbouring mountains), which can vary between . 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. Ireland has 13 Furths, or "Irish Munros";

|Real Munro. A Munro, or Furth, with prominence over ; Ireland has 5 Real Munros;

|P600 (the "Majors"). British Isles peak of any height, with prominence over ; Ireland has 26 P600s;

|Marilyn. British Isles peak of any height, with a prominence of over ; Ireland has 454 Marilyns;

|Hewitt. England, Wales or Ireland peak over , with prominence of over ; Ireland has 209 Hewitts;

|Vandeleur-Lynam. Irish peak over , with prominence over ; Ireland has 274 Vandeleur-Lynams; Arderins;

|MountainViews.