Overview
Heapstown Cairn sits quietly on a low rise at the northern edge of Lough Arrow, just west of the River Uinshin. Despite its unassuming approach, the mound is a major prehistoric landmark. At roughly 60 metres (200 ft) in diameter, it ranks as Ireland’s fourth-largest Neolithic cairn, surpassed only by the three great tombs in the Boyne Valley. The site sits in a grassy field beside the road at Heapstown crossroads, a short walk from the Bo and Arrow public house. It is designated as a National Monument (No. 152) and carries the Irish name Carn Ochtriallach, which translates to “Ochtriallach’s cairn”.
History & Archaeology
Built around 3000 BC, Heapstown is believed to be a passage-grave type monument, similar in concept to the nearby Carrowkeel Megalithic Complex. Unlike many Irish tombs, it has never been formally excavated. Archaeologists suspect the least disturbed southeast flank may still conceal an intact passage chamber, but without digging, the tomb’s internal layout remains a mystery. What we do know comes from careful observation. In 1998, researchers identified a fragment of megalithic art on a south-facing kerbstone, confirming the site’s ritual importance.
The cairn’s appearance has changed significantly over time. Early 19th-century records, including George Petrie’s 1837 sketch, show a much taller mound crowned with a standing stone. Centuries of stone-robbing for road-building and dry stone walls reduced its height, a practice only halted in the late 1800s by local resident-magistrate Captain M’C Ternan. Today, sources list the remaining height between 6 and 10 metres, depending on how the collapsed kerbstones and turf are measured. The outer ring consists of heavy limestone and sandstone blocks, some over a metre high, marking the original edge of the burial mound.
Mythology & Folklore
The cairn’s Irish name ties it directly to the Second Battle of Moytura, one of the most famous conflicts in Irish mythology. According to legend, the divine healer Dian Cécht filled the Well of Sláine with healing herbs to treat the wounded Tuatha Dé Danann. The Fomorian champion Ochtriallach responded by throwing massive stones into the well to block it. The resulting pile of rocks became Heapstown Cairn.
Another tradition identifies the mound as the burial place of Ailill mac Echach Mugmedóin, brother to the legendary Niall of the Nine Hostages. Local memory also preserves the story of the summit pillar, noted in a 1937 school folklore survey as still lying fallen nearby, before it too disappeared into the landscape. These stories give the site a distinct atmosphere, especially when the wind moves through the surrounding chestnut trees.
What to See & Do
Walking the perimeter of Heapstown Cairn is the best way to appreciate its scale. The western and north-eastern sides show the most damage from historic quarrying, while the southeast retains a more complete ring of stones. Climbing to the top rewards visitors with a 360-degree panorama. On a clear day, you can trace the ridges of the Bricklieve Mountains to the south, spot the cairns of Carrowkeel to the southwest, and look toward the Moytura ridge where the legendary battle took place. The distant peaks of Knocknarea and Carns Hill complete a horizon dotted with Ireland’s most significant ancient monuments.
The site is popular with landscape photographers, particularly at sunrise when the low light catches the stonework and casts long shadows across the pasture. A wide-angle lens helps capture the cairn against the rolling hills, and a tripod is useful during the golden hour when light levels drop quickly.
Practical Information
Heapstown Cairn sits on private land but is freely accessible to the public when the turnstile is open. The gate is only locked when livestock are grazing in the field, so a quick look at the pasture will tell you if you can enter. There is no visitor centre, ticket office, or dedicated car park. The nearest practical stopping points are a small lay-by on the N4 at Castlebaldwin, or the larger visitor car park at Lough Arrow. From either location, follow the signposted path to the right of the crossroads.
The walk from the road is short and the ground is generally even, though the field can become boggy after heavy rain, so sturdy footwear is recommended. There are no toilets or refreshments on site; the nearest amenities are in Castlebaldwin and Ballindoon. The monument is fully exposed to the wind, so visiting on a calm day or bringing a light layer will make the experience more comfortable.
Getting there:
- From Dublin: Take the N4 to Castlebaldwin, turn right toward Ballindoon, stay right at the first junction, then after 3 km take the left at the next junction. Heapstown Cairn is sign-posted 2 km on the right.
- From Belfast: Follow the A6 to Derry, then the A5 to Lifford, continue on the N15 to Sligo Town, join the N4 to Castlebaldwin and follow the local directions above.
Nearby Attractions
Heapstown sits in one of Ireland’s densest concentrations of prehistoric monuments. Within a short drive you can visit the Carrowkeel Megalithic Complex, a cluster of 22 passage tombs set in a quiet valley. The vast Carrowmore Megalithic Cemetery lies roughly 15 km to the west, while the iconic Queen Maeve cairn atop Knocknarea offers a contrasting coastal panorama. For a change of pace, the calm waters of Lough Arrow provide an excellent spot for a lakeside walk or picnic before heading back to the ancient stones.