Hidden high above Glencar Valley in County Sligo, the Devil's Chimney is one of Ireland's most dramatic waterfalls — but it comes with a catch. You're not guaranteed to see it. Known in Irish as Sruth in Aghaidh an Aird, the waterfall pours from the Dartry Mountains over the huge limestone cliffs above Glencar Lake. After heavy rainfall it can be spectacular, with water plunging down the sheer rock face into the valley below. But during prolonged dry weather, the flow can reduce to little more than a trickle — and sometimes virtually disappear altogether.

Then there's the wind. When strong winds sweep through Glencar Valley, they can catch the falling water and blow it back upwards over the cliff. This extraordinary sight is behind the waterfall's Irish name, which translates as 'stream against the height.' Add a short but fairly steep woodland loop, wonderful views over Glencar Lake and the fact that nearby Glencar Waterfall is only a couple of kilometres away, and this is one of our favourite waterfall walks in the northwest.

The official trail is a 2.5 km loop walk taking approximately one hour, graded as moderate by Sport Ireland with around 130–150 metres of ascent. Although it's short, there is a decent climb involved. The walk begins through a kissing gate before entering woodland, then starts climbing gradually, taking you higher above Glencar Lake. As you gain height, you'll find several places to stop, rest and enjoy the view. The woodland is one of the nicest parts of the trail — rather than simply climbing across an exposed hillside, much of the route takes you through trees beneath the enormous limestone cliffs of the Dartry Mountains.

Some of the yew trees growing on the steep slopes are believed to be extraordinarily old — Sligo Walks suggests some could be as much as 1,000 years old. As you approach the higher section of the trail, you'll reach several viewing areas. One branch takes you towards a viewpoint almost directly beneath the Devil's Chimney, where looking upwards gives you a real appreciation of the scale of the cliffs. Other viewpoints higher on the trail provide benches with views not only towards the waterfall but back across Glencar Lake and the surrounding valley. Don't rush this section — the waterfall might be the reason you came, but some of the views back across Glencar are just as impressive.

The Devil's Chimney and Glencar Waterfall are only around 2 km apart, but they're completely different experiences. Glencar Waterfall is around 15 metres high and extremely accessible — you park, take a short woodland walk and you're there. The Devil's Chimney is much taller, wilder and requires a proper uphill walk. Doing both gives you the best of each. We'd start with the Devil's Chimney walk while you've got plenty of energy, then head down to Glencar Waterfall afterwards — where the teaSHED café provides a well-earned reward. For us, that's the ideal way to experience Glencar Valley.