This is a list of mountains in Britain and Ireland by height and by prominence. Height and prominence are the most important metrics for the classifications of mountains by the UIAA; with isolation a distant third criterion.[lower-alpha 2][2] The list is sourced from the Database of British and Irish Hills ("DoBIH")[lower-alpha 3] for peaks that meet the consensus height threshold for a mountain, namely 600 metres (1,969 ft); the list also rules out peaks with a prominence below 30 metres (98 ft) and thus, the list is therefore precisely a list of the 2,754[lower-alpha 4] Simms in the British Isles (as at October 2018).[3][4] Many classifications of mountains in the British Isles consider a prominence between 30–150 metres (98–492 ft) as being a "top", and not a mountain; however, using the 30 metres (98 ft) prominence threshold gives the broadest possible list of mountains. For a ranking of mountains with a higher prominence threshold use:

• List of Marilyns in the British Isles, for ranking by height and by prominence, of peaks with prominence over 150 metres (492 ft); or
• List of P600 mountains in the British Isles, for ranking by height and by prominence, of peaks with prominence over 600 metres (1,969 ft)

Highest mountains in Great Britain ("Simms" classification)
Ben Nevis, in the Scottish Highlands, is the highest mountain in The British Isles
Highest point
Elevation	over 600 m (1,969 ft)
Prominence	over 30 m (98 ft)
Geography
Location	2,755 British Isles: 2,191 Scotland 223 Ireland[lower-alpha 1] 192 England 150 Wales 1 Isle of Man

As of 31 December 2021, 7,098 people had climbed all 282 Scottish Munros,[5] as of April 2020 11 people had climbed all 1,557 Marilyns of Great Britain,[lower-alpha 5][6] while as of July 2021 only 4 people have completed the 2,531 Simms of Great Britain,[lower-alpha 6] Ken Whyte (Cruachan Beag 21/09/2010), Iain Thow (Cut Hill 07/06/2015), Michael Earnshaw (Cruach Fhiarach 16/07/2019) and Rob Woodall (Sgurr Dhonuill West Top 28/06/2021). The first three have also completed the Irish and IOM Simms too, so including all 2,755 Simms of the British Isles.[7] On 5 December 2018, the BBC announced that Foel Penolau had been re-surveyed and promoted to Hewitt status (and by definition, to Simm status).[8] Also, Cyrniau Nod has been replaced as a Marilyn (hill) by Foel Cedig.

Coverage of Simms

Despite using the lower threshold for prominence of 30 metres (98 ft), the UIAA threshold for an "independent" peak,[2] one Scottish Munro is missing, namely Maoile Lunndaidh whose official prominence changed to 11 metres (36 ft) in 2014;[lower-alpha 7][lower-alpha 8] As of October 2018^[update], the list of 2,754 British Isles Simms contained:

Simms by height by prominence

This list was downloaded from the DoBIH in October 2018, and includes all British and Irish peaks with a prominence below 30 metres (98 ft).[lower-alpha 3] Note that topographical prominence is complex to measure and requires a survey of the entire contours of a peak, rather than a single point of height.[12] These tables are therefore subject to being revised over time, and should not be amended or updated unless the entire DoBIH data is re-downloaded again. The default table ranking is by height, so where the table is sorted by for example Region, the table will list the mountains within each Region by order of height.