What makes a hill a Marilyn?

A hill needs to have a drop of at least 150 metres (492 feet) on all sides before you can climb anything higher. It doesn't matter how high the summit is above sea level—it's all about how much the hill stands out from its neighbours.

How many Marilyns are there in total?

Alan Dawson’s revised 2025 list contains 1,550 Marilyns in Great Britain. Irish and Manx hills with at least 150m prominence are recorded separately and are not part of the revised British list.

What's the easiest Marilyn to climb?

Some Marilyns have a road very close to the summit, including Bishop Wilton Wold. At the other extreme, Sgùrr Dearg’s Inaccessible Pinnacle is a Moderate rock climb, while Stac an Armin and Stac Lee require difficult sea landings and climbing.

The Classification Index

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 August 202610 min read