Mayo, Sligo & Wild Nephin Guides & Walking Routes Library

Simms: the hill category that tidied up the lists

If you've ever wondered why British hill lists seem unnecessarily complicated, Simms offer a rare moment of clarity. Introduced by Alan Dawson in 2010, a Simm is any summit over 600 metres with at least 30 metres of drop all round – a definition that consolidated several older, overlapping lists like Murdos, Corbett Tops, Graham Tops and Hewitts into something more coherent.

28 Sept 2026Read

Guide

Marilyns: Why a 150-Metre Drop is the Real Test of a Hill

Think altitude is everything? See why a 150-metre drop identifies Britain’s 1,550 Marilyns, and how the list changed in 2025.

24 Aug 2026Read

Guide

The Hewitts: A Study in Prominence and Persistence

A classification that ignores the "pretty" peaks to focus on the physical effort and distinct logic of the high ground.

24 Aug 2026Read

Guide

The HuMPs: The Geography of Independence

Forget the highest peaks and look at the hills that stand on their own—this is the fascinating, mathematical world of the HuMPs.

24 Aug 2026Read

Guide

Vandeleur-Lynams and the 15-metre line between an Irish summit and a subsidiary top

The Vandeleur-Lynam list uses a 15-metre prominence threshold, low enough that it includes subsidiary tops alongside independent mountains. As at 31 December 2023 it contained 275 locations above 600 metres: 209 mountain summits, 14 hill summits just short of 2,000 feet, and 52 subsidiary tops with less than 30 metres of prominence.

03 Nov 2026Read

Guide

The Dodds: When Three Regional Lists Became One Metric Classification

Between 500 and 600 metres sits a collection of hills that used to be split across Deweys, Donald Deweys and Highland Fives—until the idea emerged in 2014 to unify them under a single name that works across Britain.

02 Nov 2026Read

Guide

Simms: the hill category that tidied up the lists

If you've ever wondered why British hill lists seem unnecessarily complicated, Simms offer a rare moment of clarity. Introduced by Alan Dawson in 2010, a Simm is any summit over 600 metres with at least 30 metres of drop all round – a definition that consolidated several older, overlapping lists like Murdos, Corbett Tops, Graham Tops and Hewitts into something more coherent.

28 Sept 2026Read

Guide

Marilyns: Why a 150-Metre Drop is the Real Test of a Hill

Think altitude is everything? See why a 150-metre drop identifies Britain’s 1,550 Marilyns, and how the list changed in 2025.

24 Aug 2026Read

Guide

The Hewitts: A Study in Prominence and Persistence

A classification that ignores the "pretty" peaks to focus on the physical effort and distinct logic of the high ground.

24 Aug 2026Read

Guide

The HuMPs: The Geography of Independence

Forget the highest peaks and look at the hills that stand on their own—this is the fascinating, mathematical world of the HuMPs.

24 Aug 2026Read

Guide

Vandeleur-Lynams and the 15-metre line between an Irish summit and a subsidiary top

The Vandeleur-Lynam list uses a 15-metre prominence threshold, low enough that it includes subsidiary tops alongside independent mountains. As at 31 December 2023 it contained 275 locations above 600 metres: 209 mountain summits, 14 hill summits just short of 2,000 feet, and 52 subsidiary tops with less than 30 metres of prominence.

03 Nov 2026Read

Guide

The Dodds: When Three Regional Lists Became One Metric Classification

Between 500 and 600 metres sits a collection of hills that used to be split across Deweys, Donald Deweys and Highland Fives—until the idea emerged in 2014 to unify them under a single name that works across Britain.

02 Nov 2026Read

Guide

Simms: the hill category that tidied up the lists

If you've ever wondered why British hill lists seem unnecessarily complicated, Simms offer a rare moment of clarity. Introduced by Alan Dawson in 2010, a Simm is any summit over 600 metres with at least 30 metres of drop all round – a definition that consolidated several older, overlapping lists like Murdos, Corbett Tops, Graham Tops and Hewitts into something more coherent.

28 Sept 2026Read

Guide

Marilyns: Why a 150-Metre Drop is the Real Test of a Hill

Think altitude is everything? See why a 150-metre drop identifies Britain’s 1,550 Marilyns, and how the list changed in 2025.

24 Aug 2026Read

Mayo, Sligo & Wild Nephin Library

Hiking Route Guides

Mweelrea via Silver Strand

Croagh Patrick via Cosán Phádraig from Murrisk

Hill Lists and People

Simms: the hill category that tidied up the lists

Marilyns: Why a 150-Metre Drop is the Real Test of a Hill

The Hewitts: A Study in Prominence and Persistence

The HuMPs: The Geography of Independence

Vandeleur-Lynams and the 15-metre line between an Irish summit and a subsidiary top

The Dodds: When Three Regional Lists Became One Metric Classification

Simms: the hill category that tidied up the lists

Marilyns: Why a 150-Metre Drop is the Real Test of a Hill

The Hewitts: A Study in Prominence and Persistence

The HuMPs: The Geography of Independence

Vandeleur-Lynams and the 15-metre line between an Irish summit and a subsidiary top

The Dodds: When Three Regional Lists Became One Metric Classification

Simms: the hill category that tidied up the lists

Marilyns: Why a 150-Metre Drop is the Real Test of a Hill

Landscape and Place Names

Slieve, Sliabh, and Sleeve: When One Mountain Word Has Three Spellings

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