You walk 50 metres up in the air for very little effort: that’s the appeal of the Borris Viaduct. Sixteen limestone arches carry an old railway deck high across the Mountain River valley below the Carlow village of Borris, and since 2021 you can stroll straight out along the top, 500 metres each way, with the Blackstairs Mountains and Mount Leinster filling the view. It’s a short outing – the full loop, taking in the path under the arches, is about 1.5km and 30 to 45 minutes – so come for the height and the views, not for a long day’s walking, and bring the kids, because the railed deck is buggy-friendly and as flat as walking gets.
The structure and its history
The viaduct was designed by the engineer William Richard Le Fanu (1816–1894) and built around 1860 to carry the Bagenalstown–Wexford railway, though the line through Borris was already running by 1858, so the exact finishing date is one for the record-keepers. The whole structure runs to roughly 800 metres; the walkable deck across the river is the 500-metre central span. It’s a genuinely impressive piece of monumental railway engineering, the kind of thing that must have astonished a farming community when the first steam engine crossed it.
The man who made it happen was Arthur MacMurrough Kavanagh of Borris House, who pushed for the railway to reach the town and instigated the viaduct. Kavanagh is one of the more extraordinary figures in Irish history: born in 1831 without fully formed arms or legs, he nonetheless rode, shot, sailed, travelled across Persia and India, and sat as a Westminster MP. His wife, Lady Harriet Kavanagh, set up a successful lace-making industry in Borris around 1857 to bring work to the town.
The trains didn’t last. Passenger services ended in 1931, goods traffic ran until 1947, and the line closed for good on 1 January 1963, a century and change after the first sod was cut. The viaduct then sat disused until Carlow County Council restored it, with €654,820 from the Rural Regeneration and Development Fund; the finished walk was officially opened in July 2021. The council added the railings along the deck, which were needed – the original parapets were low.
Walking it
The walk starts from the car park beside Borris Vocational School, off the R702 (there’s an older car park on the R702 itself too). It’s part of the Slí na Sláinte network and is free. Cross the deck for the views, then drop down onto the loop that runs underneath, where you get the better sense of the scale of the piers and the river running through the gorge. Look out for the old railway quarter-mile marker post – it reads 74¾ – a small survivor of the working line. Cycling is allowed as well as walking.
One honest note: there are no toilets at the viaduct, so use the facilities in Borris village before you set out.
Around Borris
Borris House, in the village, is the Tudor-Revival ancestral home of the MacMurrough Kavanaghs – descendants of the Kings of Leinster – and one of the few great Irish houses still held by the original family; it opens for tours and hosts the Festival of Writing and Ideas each summer. Borris itself is a handsome granite estate village with a clutch of good pubs and the Step House Hotel, and it makes a fine base for the Blackstairs and the climb to Mount Leinster from the Nine Stones. The nearest train stations are at Muine Bheag (Bagenalstown), Carlow town or Kilkenny.