Being the Black Mountains can’t be easy. In fact, it must be like being the youngest in a family with four siblings. Making up just a quarter of the ranges that define the Brecon Beacons national park, it has to fight to be noticed. It seems that this range – which spreads east of the park as far as the border with Herefordshire in England – is forever cast in the shadow of the Brecon Beacons, Black Mountain (in the west and with virtually the same name) and Fforest Fawr. This, however, is good news for wilderness lovers. Thanks to the crowd-pulling appeal of the others, it’s actually the perfect place to spend your own secluded night watching the stars.

Physically separated from its siblings by the river Usk, there is no denying that the Black Mountains landscape looks a little different. There are fewer crashing waterfalls and steep escarpments. Instead, you’ll find high, rolling sandstone, studded with lumps of limestone and plenty of silty riverbeds.

The best thing about this area – aside from the lack of crowds – is its topography, which means that once you get up high, you stay high. So, planning a high-level meander is easy, as is pitching your tent on one of the many flattened summits. It also scores points on natural history grounds: its slopes support unusual plants such as whitebeams, liverworts and various lichens, plus such breeding upland birds as red grouse and golden plover.

And it’s not only birds that take to the air up here: this area is also popular with gliders. As you make your way along the tops that line the Grwyne valley, listen out for the whoosh from those manmade wings. And later, as you watch the day turn to dusk, fire up your camping stove and watch the lights begin to twinkle in the villages at your feet.

Pre-trip

There is nothing in the way of shops at the start, so you will need to collect supplies before you arrive. Abergavenny is the nearest town; other options are Crickhowell, Hay-on-Wye (north) or Hereford (north-west). Any one of these is also an option for an overnight if you fancy a B&B or hotel pre-trip.

Public transport

This is another wild weekend that lies beyond public transport. The nearest you can get to the start is Wern Gifford (via bus from Abergavenny or Hereford). But it’s still a 15km walk from there so you may consider a taxi or else have to bring your car.

Top tip

Take plenty of water with you. There is nowhere easy to collect it on this route – without climbing a long way down and then back up again. If you get stuck after Rhos Dirion you can descend to Grwyne Fawr to collect some, though it will be a pain.

The plan

Day 1
1. From the car park follow the path which will lead you temporarily out onto the road. Turn right and follow it for a few steps then take the path on your right leading uphill. Soon afterwards, take the less-defined path that heads up sharply in a northerly direction and follow it for just over half a mile up onto the ridge above the valley.

2. Here you’ll join a much more defined track that runs north-west to south-east. Turn left onto it and follow it north-west. Already the views are spectacular and though it can be boggy up here the going is straightforward, so continue all the way to Twyn Talycefn and beyond, staying true to the north-west line. You will reach the top of Rhos Dirion. It’s a fairly flat summit but its position right on the edge of this huge plateau allows commanding views into the towns and villages beyond – and also of the route you’ll take tomorrow. On a windy day you might want to consider moving on to the next stage and finding one of the hollows around Mynydd Bychan that offer a little more shelter. Otherwise pitch your tent/bivvy, get the stove on and enjoy the views.

Day 2
3. Leave the summit by the obvious path south-west towards the col and fence line. Continue, taking the gate through the fence. Be sure not to pick up the path that sweeps you out to Y Grib; instead take the left-hand path at the fork, bearing south-east.

4. This next part is probably the worst for bogs and peat hags, so perhaps grab a snack before you knuckle down to it. Then follow the path, tracking roughly south-east to the summit of Waun Fach. The path undulates, with many diversions around standing water, but once at Waun Fach the end is in sight. Continue along this boggy plateau, first descending then ascending, until you reach the summit of Pen y Gadair Fawr.

5. The views from here make the effort well worth it. Linger a while to enjoy your reward then, when you’re ready, turn your back on the summit and look north-east. You should see a rough path leading off in the same direction. It’s not on the map, but is fairly well defined and cuts downhill alongside (but not in) the forestry land, making the descent quick, if fairly steep. Follow this all the way down. You’ll pass the remains of old homesteads just before reaching the stream, where handy boulders enable you to cross easily into the woods.

6. From here turn right onto the path and follow it along under cover of the trees, keeping the stream to your left. Soon you’ll come to a bridge. Turn left to cross it and then make your way up to the minor road. Turn right onto it and shortly you’ll reach the car park that was your starting point.

Further information

Black Mountains breconbeacons.org/black-mountains, visitcrickhowell.co.uk, visitabergavenny.co.uk and visitmidwales.co.uk

Taken from Wilderness Weekends: Wild Adventures in Britain’s Rugged Corners, published by Bradt for £14.99. The publisher is offering Guardian readers a 35% discount on the book; visit bradtguides.com and enter the code GUARDIAN at the checkout. Offer valid until 31 May 2015