Marilyns are hills in the British Isles with a relative height of at least 150 metres regardless of their absolute height. To date, 2008 Marilyns have been identified: 1215 in Scotland, 387 in the Republic of Ireland, 179 in England, 156 in Wales, 66 in Northern Ireland and 5 on the Isle of Man. The list of Marilyns in Britain was compiled by Alan Dawson in The Relative Hills of Britain, and continues to be updated as the heights for hills and the passes between them are more accurately surveyed. The Irish part of the list was produced by Clem Clements.

On his website, Aaron Maizlish has written a lengthy section on orometry (the measurement of mountains) in which he discusses what he calls the prominence adjusted lineage area or domain of a peak. Using the techniques discussed there, I have produced a series of maps (so far covering all of Wales and England, and Scotland south of the Central Belt) showing how the country is divided up into 150 m, 300 m, 600 m and 900 m.

All of these maps are in an equirectangular projection with a standard parallel of 54°26'N, and have a scale of 3" or 6" of latitude per pixel. This is equivalent to scaling the eastings by 58.16% from plate carrée.

Copyright, © Richard Smith, 2009–10.
The maps on this page are available under the terms of the Creative Commons cc-by-2.0 licence.