Knockroe – a twin-solstice passage tomb

Overview

Most Irish passage tombs are built to catch one solar event. Knockroe catches two. The eastern of its two stone-lined chambers is aligned to the winter-solstice sunrise on 21 December, and the western chamber frames the setting sun on the same day – a double alignment that makes this small Kilkenny cairn one of the more unusual Neolithic monuments in the country.

Knockroe sits on a south-west-facing ridge overlooking the Lingaun River, a tributary of the Suir, about 10 km north of Carrick-on-Suir. Locally it is known as The Caiseal. The two chambers sit within a cairn that was once capped with earth and quartz, and the whole site is a National Monument (no. 655) in the care of the Office of Public Works. When exactly it was built is not settled: estimates run from around 3,000 BC (Heritage Ireland) to as early as 3400 BC, so it is safest to call it roughly 5,000 years old.

Name & Landscape

The name Knockroe translates from the Irish Cnoc Rua as “the red hill”, a direct reference to the distinctive iron-rich soil that colours the ridge. The tomb sits on a deliberately prepared platform that levels the natural slope, giving the monument a stable base despite the undulating terrain. From the cairn, the view stretches across the Lingaun Valley toward the larger mound on the summit of Slievenamon. The surrounding area is thick with prehistoric activity, dotted with other megalithic sites, medieval high crosses, and the weathered trackways of historic slate quarries.

History & Archaeology

Knockroe appears in 19th-century Ordnance Survey records, though the first written description came from Canon William Carrigan in 1905. Systematic excavation only began in 1990, led by Professor Muiris O’Sullivan of University College Dublin. The digs revealed a phased construction history: the eastern passage and chamber are the earlier of the two, with the western chamber added later during a significant enlargement.

The excavations uncovered cremated human remains alongside bone and antler pins, beads, pendants, and pottery, showing the tomb was used repeatedly over centuries for burial and ritual. About thirty stones carry spirals, cup-marks, and zigzags, one of the largest collections of megalithic art outside the Boyne Valley. A stone in the western chamber bears a motif close to the carvings at Gavrinis in Brittany, hinting at wider Atlantic contact during the Neolithic. A quartz frieze lines the eastern façade, echoing the quartz-capped cairns of the east coast. According to the Discover Ireland account, a roof-box in the western chamber is set to channel the solstice sunset onto a tall red-sandstone stone – the same trick as Newgrange, but at dusk rather than dawn.

What to See & Do

• Dual Solstice Alignment – Knockroe’s twin chambers offer a unique astronomical experience. The eastern chamber captures the winter-solstice sunrise, while the western chamber aligns with the sunset. The precise geometry required to achieve this dual alignment speaks to the advanced observational skills of Ireland’s first farmers.
• Megalithic Art Trail – Walk the stone-lined passages and study the spirals, concentric circles, and zigzags carved into the kerbstones. The carvings are best viewed in the soft light of early morning or late afternoon, when shadows bring the shallow grooves into relief.
• Valley Vistas – The tomb’s elevated position provides sweeping views across the Lingaun Valley. On clear days, you can trace the line of sight to Slievenamon and spot the faint outlines of other ancient monuments scattered across the farmland.
• Community Solstice Gatherings – Around 21 December, local volunteers often host informal gatherings near the site. Expect shared stories, warm drinks, and occasional talks by archaeologists or local historians.
• Explore the Wider Heritage Route – Knockroe is one node in a wider prehistoric landscape that takes in Bawnfree and the Kilmacoliver Stone Circle. A short drive connects you to the High Crosses at Ahenny, the cairn on Slievenamon, and the medieval ruins of Jerpoint Abbey and Kells Priory. The nearby town of Callan gives a glimpse into medieval parish life and traditional craft workshops.

Visiting the Winter Solstice

The solstice draws the largest crowds of the year. If you can only come once, make it the 21 December sunset: the western roof-box is the distinctive feature here, and the gathering itself is part of the occasion. For the sunrise, arrive well before dawn to get a position at the eastern chamber, as the light lasts only a few minutes. Local volunteers usually manage the parking and often bring mulled wine and mince pies; in some years Professor O’Sullivan himself is on hand to talk visitors through the alignment. The ground is often wet and the ridge is exposed, so pack waterproof layers, a hat, and sturdy boots. A headtorch is essential for crossing the field after dusk.

Practical Information

Knockroe is an unguided heritage site managed by the Office of Public Works. The monument remains in its natural field setting, and visitors are asked to stay on established paths and treat the stones with care.

Getting There

From Carrick-on-Suir, take the R697 north for approximately 10 km, then turn left onto the R698. Continue to the first crossroads, turn left again, and follow the smaller lane that leads directly to the fenced-off site. Parking at the site is very limited: a local farmer opens his farmyard for cars (it’s signposted), and at the solstice community volunteers direct the traffic. The lane is narrow, so allow extra time if you meet oncoming traffic.

Visitor Resources

• Official tourism page: Discover Ireland – Knockroe Passage Tomb
• Heritage Ireland site (unguided information): Heritage Ireland – Knockroe Passage Tomb
• Detailed archaeological report (UCD): Excavation Report
• Podcast interview with Prof. O’Sullivan: Amplify Archaeology – Episode 28

Plan your visit on a weekday outside the solstice window for a quiet, reflective experience. The site is completely open, allowing you to sit on the kerbstones and trace the sightlines across the valley at your own pace.