The second-highest point in the Southern Uplands and the highest point in the Scottish Borders, it has an elevation of 840 metres, a prominence of 653 metres (and thus is a "major") and an isolation of 81 kilometres.

Like many of its neighbours it is smooth, rounded and grassy, although the surrounding glens have very steep sides — country somewhat akin to the Cheviots or the Howgill Fells.

The hill is most easily climbed from the Megget Stane to the south, beginning at an elevation of 452 m (1,483 ft), but is also frequently climbed from the villages near its base, or as part of a long, 50 km (30 mi) trek across the local area between the towns of Peebles and Moffat.

On the summit is the highest VOR beacon in the UK,[4] and also a radio tower.

The administrative "county" boundary of Peeblesshire and Selkirkshire thus temporarily crossed Broad Law summit between 1891 and 1974.