A Marilyn is a hill of any height with a drop of 150 metres or more on all sides. The Marilyns in Britain and the Isle of Man were first listed in the book The Relative Hills of Britain (RHB) by Alan Dawson, published by Cicerone Press in April 1992. At that time there were 1542 Marilyns, which had increased to 1557 by the end of July 2018. Details of subsequent changes have been published in a series of update sheets from 1995 onward. A summary of the main changes since 1992 are set out below.
| Year | Marilyns | Promoted | Demoted | Notes |
| 1992 | 1542 | First publication of the list of Marilyns. | ||
| 1995 | 1551 | Cruim Leacainn (4A) The Bochel (8) Giur-bheinn (20B) Beinn Bhragair (24A) Sell Moor Hill (28A) Mynydd Rhyd ddu (30C) Craig y Castell (30F) Disgwylfa Fawr (31A) Cefn Cenarth (31B) Carn Gafallt (31C) Mynydd Dinas (32C) Swinside (34B) Lovely Seat (35A) Aconbury Hill (38B) Cheriton Hill (42) |
Sgorr Tuath (16F) Cruach Bhuidhe (19C) Cunnigill Hill (22) Hedgehope Hill (33) Cushat Law (33) Scafell (34B) |
First RHB updates, in May 1995 and November 1995.
Fifteen new Marilyns are discovered. Six hills are removed the list of Marilyns. |
| 1996 | 1549 | Harter Fell (34C) Baystones (34C) |
The first list of Submarilyns is compiled and distributed. | |
| 1997 | 1551 | Abberley Hill (38B) Milk Hill (39) |
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| 1999 | 1551 | Swyre Head (41) Nine Barrow Down (41) |
Abberley Hill (38B) Milk Hill (39) |
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| 2001 | 1552 | Baystones (34C) | ||
| 2005 | 1554 | Meall Chomraidh (2A) Arnside Knott (34D) |
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| 2008 | 1555 | Sail Chalmadale (20C) | First Marilyn change arising from a survey using differential GPS equipment by GJ Surveys. | |
| 2009 | 1556 | Creag na Criche (1A) Mynydd y Cwm (30C) |
Raw Head (36) | |
| 2010 | 1554 | Baystones (34C) Lovely Seat (35B) |
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| 2013 | 1557 | Killyleoch Hill (27C) Lamberton Hill (28A) Mynydd Anelog (30A) |
First Marilyn changes arising from surveys using differential GPS equipment by Alan Dawson. | |
| 2014 | 1556 | Creag an Amalaidh (16D) | Cruim Leacainn (4A) Troweir Hill (27B) |
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| 2015 | 1556 | Sithean Mor (13A) Kirriereoch Hill (27B) |
Stob na Boine Druim-fhinn (19C) Swyre Head (41) |
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| 2018 | 1557 | Beinn Dearg (16A) | The first new Marilyn for three years, surveyed by Jon Metcalf |
