A Marilyn is a hill or mountain in the United Kingdom, Ireland or surrounding islands with a prominence of at least , regardless of its absolute height or other characteristics such as topographic isolation.
Marilyns may include true mountains (with heights above ) as well as smaller hills, as long as they meet the prominence criterion.
, there were 2,010 recorded Marilyns.
The Marilyn classification was created by Alan Dawson in his 1992 book The Relative Hills of Britain. The name was coined as a punning contrast to the Munro classification of Scottish mountains above , which has no explicit prominence threshold, being homophonous with Monroe. The concept was later extended to Ireland by E. D. "Clem" Clements.
Marilyns were the first of several British Isles classifications based solely on topographic prominence, including the P600s, the HuMPs, and the TuMPs. Determining prominence is more complex than measuring absolute elevation, requiring surveys of each contour line around a peak; therefore lists based on prominence are periodically revised.
Although many of the largest mountains in the islands, such as Ben Nevis, Carrauntoohil, Scafell Pike and Snowdon, are Marilyns, othersâÂÂincluding Cairn Gorm and some Munros, as well as hills such as Bowfell, the Langdale Pikes and Carnedd DafyddâÂÂare not, as they lack sufficient relative height compared to nearby higher "parent" peaks.
there were 2,010 Marilyns in the British Isles: 1,218 in Scotland (including 202 of the 282 Scottish Munros; Munros with Marilyn-prominence are sometimes called Real Munros), 454 in Ireland, 174 in England, 159 in Wales and 5 in the Isle of Man. On 13 October 2014 Rob Woodall and Eddie Dealtry became the first people to climb all 1,557 Marilyns in Great Britain. , 11 Marilynists had climbed all Marilyns then listed in Great Britain. , 275 had entered the Marilyn Hall of Fame by climbing over 600 Marilyns.
In June 2025 Dawson published The Revised Relative Hills of Britain: The Marilyns (Pedantic Press, ), listing 1,550 Marilyns in Britain (excluding Ireland and the Isle of Man) and 99 hills that narrowly fail to qualify (submarilyns). this list is used by the Database of British and Irish Hills to define a Marilyn, with a separate category for The Irish and Manx Marilyns.
Marilyns include some of the largest mountains in the British Isles as well as relatively modest hills:
, the list of 2,010 British Isles Marilyns contained:
This list was downloaded from the Database of British and Irish Hills ("DoBIH") in October 2018, and are peaks the DoBIH marks as Marilyns ("M"). As topological prominence is complex to measure, these tables are subject to revision over time and should not be amended or updated unless the entire DoBIH data is re-downloaded. The tables are structured to show rankings by height and prominence over the entire British Isles, or by region.
Since the table was downloaded, the following changes have been made to the list of recognised Marilyns:
The DoBIH uses the following codes for the various classifications of mountains and hills in the British Isles, which many of the above peaks also fall into:
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