Carnethy Hill, Scald Law, Hare Hill, Black Hill, Harbour Hill, Capelaw Hill, Fala Knowe and Castlelaw Hill Loop

This long Pentland Hills circuit packs a great deal into roughly 23 km / 14.3 miles, with about 1,300 m / 4,265 ft of ascent, so although it is often classed as medium, it can feel much tougher in poor weather or if the ground is wet and energy-sapping. The route links a broad chain of rounded but exposed summits above the reservoirs and glens south-west of Edinburgh, beginning near the Castlelaw area above the A702, close to Castlelaw Hill Fort and the Castlelaw car park area near Penicuik. Castlelaw Hill Fort itself is on Castle Knowe in the Pentlands, about 1 mile / 1.6 km north-west of Glencorse and 2.5 miles / 4 km south-west of Lothianburn Junction, with parking about 0.2 miles / 0.3 km from the fort. (historicenvironment.scot)

Expect a route that starts comparatively gently before committing to repeated climbs and descents across a high, open ridge system. The first major objective is usually Carnethy Hill, one of the most distinctive Pentland summits, followed by the pull to Scald Law, the highest point in the Pentlands at 579 m / 1,900 ft. From there the loop continues over a succession of lesser but still worthwhile tops including Hare Hill, Black Hill, Harbour Hill, Capelaw Hill, Fala Knowe and Castlelaw Hill, creating a day that feels varied rather than repetitive. The terrain is a mix of engineered hill paths, grassy trods, moorland sections and steeper, rougher summit approaches where footing can become loose, muddy or slick after rain. The cumulative ascent is what makes this outing demanding: no single climb is extreme by mountain standards, but the repeated ups and downs steadily add up. (en.wikipedia.org)

What the route feels like on the ground

The early climb toward Carnethy Hill is one of the sharper efforts of the day, and it quickly opens wide views over the reservoirs, the lower Pentland ridges and, on a clear day, toward Edinburgh and the Firth of Forth. Carnethy is a broad, airy hill with a strong sense of height despite its modest elevation, and it often gives hikers their first taste of the wind exposure that defines much of this loop. The onward traverse to Scald Law is more open and rolling, but the weather can change the character of this section completely. In calm conditions it is a rewarding ridge walk; in strong wind, low cloud or winter conditions it becomes a serious navigation leg where visibility can collapse quickly.

Beyond Scald Law, the route becomes more of a high moorland circuit than a simple out-and-back to a single summit. Hare Hill, Black Hill and Harbour Hill tend to feel quieter and more spacious, with fewer obvious landmarks and a stronger sense of being out on the plateau. This is where pacing matters. The hills are not especially technical, but the broad shoulders, peatier ground and occasional indistinct path lines can slow progress. Capelaw Hill and Fala Knowe add more undulation before the route swings back toward Castlelaw Hill, where the landscape begins to reconnect with the historic and lower-lying edge of the range. HiiKER is especially useful here for keeping track of the line across the less-defined middle and later sections.

Landmarks, scenery and natural character

One of the pleasures of this loop is how often the perspective changes. To one side are the Pentland reservoirs and folds of glen; to the other are open views across Midlothian farmland and toward the outskirts of Edinburgh. The reservoirs visible from different parts of the route help anchor the landscape, while the rounded volcanic hills give the skyline its classic Pentland shape. The hills here are largely treeless on the upper ground, so the scenery is defined by heather, rough grass, peat, burns and broad skies rather than woodland.

Wildlife is typical of upland moor and reservoir-edge habitat. Hikers may see or hear skylarks, meadow pipits, curlews and other upland birds, while birds of prey are always worth watching for over the ridges. Around wetter ground and lochans, amphibians and invertebrates thrive in season, and the moorland vegetation changes character through the year, from fresh greens in spring to purple heather tones later in summer. The Pentland Hills Regional Park also notes the area’s wider wildlife interest as part of its natural history. (pentlandhills.org)

Historical significance of the area

This is not just a hill day; it is a walk through a landscape with deep archaeological importance. The Pentland hilltops are scattered with ancient remains, and the regional park highlights Castlelaw Hill Fort and its souterrain as among the most notable sites in the area. There are also large cairns on Carn