Bonaly to Balerno via Carnethy

This 11-mile linear walk takes in some of the best that the Pentlands have to offer. Starting from Bonaly on the outskirts of Edinburgh, you’ll visit four reservoirs as you climb Turnhouse and Carnethy hills then continue through the picturesque Green Cleugh to reach Balerno.

Distance: 17.5 km (11 miles)
Start: Bonaly bus terminus (NT 21385 68280)
Finish: Cockburn Crescent bus stop, Balerno (NT 16450 65655)
Access: Bonaly and Balerno are both serviced by regular buses from Edinburgh; bus 10 arrives at Bonaly, while bus 44 will take you back into the city from Balerno.

The route described starts from the bus terminus at Bonaly: if you’re arriving by car, you can park at the parking area at Bonaly Country Park (NT 21140 67460). This skips the first paragraph and reduces the length of the walk by around 1km.

Part One: Chasing Phantoms

From the bus terminus at Bonaly (NT 21385 68280), follow Bonaly Road south over a bridge across the City Bypass. Pass a communications mast on your right, then Bonaly Tower on your left. The tower is now a private residence, but was once home to Lord Henry Cockburn, Solicitor General for Scotland. Cockburn was a renowned architectural conservationist to whom numerous historically significant buildings in Edinburgh owe their survival, and, curiously, served as one of the lawyers for the defence in the trial of notorious body snatchers turned serial killers Burke and Hare. Continue along the road as it climbs gently uphill to a small parking area and a gate providing entrance to Bonaly Country Park (NT 21140 67460).

Follow the path signed for Glencorse, which passes through Sanctuary Wood and out onto Bonaly Moor. From above the scenic Dean Burn Gorge, you have spectacular views back over Edinburgh and across the Firth of Forth to Fife.

Views across Edinburgh from above the Dean Burn gorge.

After reaching a small wooded area, you will pass the Bonaly Reservoir (NT 21170 66310) on your right. The reservoir was built in the 1850s to supply water for Edinburgh’s growing New Town, a purpose it no longer serves today. The earthwork to your left is actually the remains of a dam from a smaller reservoir that was replaced by the current one.

Looking across Bonaly Reservoir.

Continue towards the trees at the opposite side of the reservoir and you’ll arrive at a gate (NT 21190 66090). Pass through and bear right to follow a wall. You’ll soon find the path bends to the left between Capelaw and Harbour Hills.

The path leading from Bonaly Reservoir to Phantom’s Cleugh.

You’re entering an area known as Phantom’s Cleugh. Far from being haunted, this stretch between Capelaw and Harbour hills was named by the local rangers after an unknown individual who they nicknamed The Phantom: he was repeatedly spotted carrying out maintenance of the paths and waterways of the surrounding hills, but disappeared whenever anyone tried to thank him for his work.

Venturing through Phantom’s Cleugh.

The cleugh can be muddy, but after crossing one of the many streams that run through it you’ll leave the cleugh and cross Knightfield Rig. As the path descends, you’ll arrive at a fork. Bear right and head towards the large reservoir straight ahead of you. At a junction (NT 21400 64230), turn left following a sign for Flotterstone to reach the shore of the reservoir itself (NT 21570 64045).

Arriving at Glencorse Reservoir.

Much like Bonaly reservoir, Glencorse Reservoir (shown as Glencross on older maps) was built in the 19th Century to provide drinking water for Edinburgh and a power supply for nearby mills. Below its surface is the ruin of St Catherine’s Chapel. Today Glencourse is a popular destination for walkers due to its picturesque beauty and its ease of access from the road at Flotterstone.

Part Two: Take to the Hills

Turn left and follow the road across Kirk Bridge (“Kirk” is the Scots word for church) and along the side of the reservoir past Glen Cottage. When you reach a gate on your right signed for Flotterstone by Old Filter Beds (NT 22467 63386), go through the gate and follow the path down to the Glencorse burn.

Views along Glencorse Reservoir.

As the path reaches the burn, it bends left to follow it downstream. If you take a moment to turn to the right, you’ll find yourself at the foot of an impressive waterfall as water escapes the reservoir.

The waterfall emerging from the Glencorse reservoir.

The path follows the course of the burn, passing the Filter Beds on your right. As the name suggests, these were used to filter nearly four million gallons of water that flowed from the reservoir and turn it into drinking water. Today this job is done at a large water processing plant further downstream.

From the Filter Beds, the path continues along the side of the burn until you arrive at a junction on your right (NT 22830 63070). Follow this path to reach a small footbridge over the burn on a path signed for Scald Law. Pass through the gate and cross the bridge here to begin your ascent up the first hill of the day: Turnhouse Hill.

Beginning to climb Turnhouse Hill.

Nearby, on the slopes of the hill, was the site of the Battle of Rullion Green, which saw the rebel Covenanter army defeated by the much larger and better trained government forces. The Covenanter’s Grave, a memorial to a solder who died at the battle, can be found in the southern Pentlands on Black Law near West Linton.

The well-walked path climbs steadily uphill to reach Turnhouse Hill (NT 21265 62650). Here on the hilltop, you’re quite exposed to the elements: if the wind doesn’t blow you away, the spectacular views across the Lothians might. From here the path descends into the col ahead then rises again to Carnethy Hill, the second highest peak in the Pentlands.

Following the path from Turnhouse to Carnethy. Look out for Loganlee Reservoir on the right at the bottom of the hill.

The name Carnethy likely comes from an old British word for cairn (it’s similar to the Welsh word carneddau). As you arrive at the summit (NT 20370 61910), you’ll see that the name is quite appropriate — a vast expanse of stones adorn the peak, along with several cairns.

Views south from the summit of Carnethy Hill.

Part Three: The Priest’s Path

From the summit of Carnethy Hill, follow the path downhill to a gate in the saddle between Carnethy and Scald Law (NT 19525 61510). From here you could continue straight ahead to climb the Pentlands’ highest hill, but for now we’ll leave the peaks behind and return to lower ground.

Bear right to start your descent. This section of the route joins the Kirk Road, an old pathway used by the residents of the Logan Valley to attend church in Penicuik on the other side of the hills. The path roughly follows the fence on your right as you head downhill to the valley near the third reservoir of the day at Loganlee.

Descending along the Kirk Road towards Green Cleugh.

When the path reaches the valley floor (NT 19000 62005), bear left, signed for Balerno. After crossing the Logan Burn near Lover’s Loup (NT 18665 61865), the path enters Green Cleugh. This steep-sided valley was carved by a glacier, and leads between Black Hill and Hare Hill. Follow the path to reach a gate (NT 17915 62480), which you should pass through.

The waterfall formed by the Logan Burn as it descends into Green Cleugh.

After around 1.5km, you’ll arrive at another gate (NT 16640 62695) near Bavelaw Castle. Follow the tree-lined road here, bearing right at a junction to arrive at Redford Bridge (NT 16410 63415). To your left is Bavelaw Marsh nature reserve, while to your right is Threipmuir Reservoir.

Views across Threipmuir Reservoir from Redford Bridge.

Continue along the road past a car park and the Red Moss of Balerno. When you meet another road (NT 16655 64260), bear right and follow it downhill. From here it’s around 1.5km to Balerno (NT 16450 65655), from where you can take a bus back to the city centre.

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