Data & methodology

Every figure on Summit Register comes from, or is calculated from, the Database of British and Irish Hills. This page explains which hills we include and how each measure is worked out.

Drop is measured from the summit down to the key col; isolation is the straight-line distance to the nearest higher summit. Schematic, not to scale.

Source

Contains data from The Database of British and Irish Hills v18.6 (www.hill-bagging.co.uk/dobih), licensed under CC BY 4.0. Distances, ranks and comparisons are our own calculations. See hill-bagging.co.uk/dobih and the licence.

Which hills

The register includes every Munro and every Wainwright, and every Marilyn (a hill with at least 150 m of drop on all sides) of 600 m or more — 1,140 hills in total.

Height and drop

Heights and drops are as published in the database. Drop (also called prominence) is the height of the summit above its key col: the lowest point you must descend to on the way to any higher summit. The key col can lie many kilometres from the summit; where both grid references are on the same national grid we give the straight-line distance between them.

Isolation and neighbours

Isolation is the straight-line (great-circle) distance from the summit to the nearest higher summit among all 21,539 hills in the database. Because only listed summits are considered, the true distance to higher ground can be slightly shorter. Nearest neighbours are the closest hills within this register. Directions use eight compass points.

The skyline drawings

Each hill page opens with a skyline looking north. The summits of nearby register hills are placed at their true east–west position and true height; the slopes between them are drawn, not surveyed, and heights are exaggerated by the factor stated under each drawing. It shows how a hill sits among its neighbours, not the view from any particular point.

Ranks

Ranks compare hills within this register only (by country, county and overall). Equal values share a rank.