Lough Gowna – where the River Erne begins

Overview

Lough Gowna (Irish: Loch Gamhna, ‘lake of the calf’) is where the River Erne begins – the tangle of interconnected basins at its head are known collectively as the Gowna Lakes. It straddles the Longford–Cavan border, a shallow, weed-rich, moraine-dammed lake of about 1,800 acres, winding through drumlin country into a maze of sheltered bays and inlets. Above the eastern shore, on a drumlin ridge, sits Sonnagh Fort, a well-preserved double-banked ringfort with a long view over the water. A pike lake and an ancient earthwork within sight of each other make for an easy, unhurried day out.

Location & Getting There

Lough Gowna lies a short drive north-west of Longford town, and is easily reached by car. Several public launch sites give gravel slipways and limited parking: on the Longford side at Dernaferst, Lisanny and Dring, and on the Cavan side near Cloone, Aghanoran and Corfree. For shops, toilets and a café, Aughnacliffe is the handiest village; Ballinalee to the south has more amenities again. Sonnagh Fort sits on the ridge above the eastern shore near Aughnacliffe, a short walk up from the road.

History & Heritage

Lough Gowna & Inchmore Island

Local folklore puts the lake’s formation down to a supernatural calf that fled a well in Rathcor, carving out the waterway as it ran – hence Loch Gamhna, the lake of the calf. The lake’s most significant landmark is Inchmore (Inis Mór), a substantial island in the south-western arm. Saint Colmcille founded a monastery here in the sixth century, an early centre of learning and pilgrimage. It was raided by Vikings in 804, re-established by Augustinian monks in the twelfth century, and finally dissolved under Henry VIII in 1543. Stone foundations still mark the layout, the island served as a local burial ground into the early 1900s, and a fifteenth-century bell recovered from the ruins now hangs in the parish church at Aughnacliffe.

Sonnagh Fort

Sonnagh Fort (Ráth an tSonnaigh) is a National Monument, the best-preserved of the seven ringforts that once ringed the Aughnacliffe area. It’s a bivallate enclosure – two banks and a ditch – with an inner bank of 0.5 to 0.9 metres, an outer bank up to 1.9 metres, and a circumference of about 46 metres. Like most Irish ringforts, it most likely dates to the early medieval period, when such enclosed farmsteads were built the length of the country. A natural spring just outside would have watered its occupants. The name sonnach means ‘palisade’, which is what the double bank and ditch once carried.

Activities & Recreation

Fishing

Lough Gowna is principally a pike lake, and a well-regarded one. It’s shallow – averaging 2 to 8 metres, dropping to about 15 metres near Dring – and weedy, which is exactly what the pike like. Fishing is best early in the season (March to May) and again in autumn (September to November). Perch and roach come from the boats working the weedier shallows near the launches.

Boating, Kayaking & Paddle-boarding

The lake’s sheltered bays and calm surface make it ideal for small craft. Kayaks and paddle-boards can be launched from any of the public slipways, offering a peaceful way to navigate the intricate shoreline and reach Inchmore Island. The lack of heavy commercial traffic means visitors can often enjoy complete solitude on the water.

Walking, Wildlife & Picnics

For a set walk, Derrycassan Woods on the Cavan side has well-kept trails of up to 3 km, a playground at the entrance and, more often than not, a coffee van in the car park – an easy family option, with views over the lake to Cygnet Island. Elsewhere, gentle paths follow much of the shoreline through planted woodland and bog fringe. The lake is an important wintering ground for wildfowl: mute and whooper swans and wigeon gather here, and Cygnet Island is the place to watch them. The flat ground makes it easy to find a quiet picnic spot by the water, with Sonnagh Fort a natural extension for a longer stroll.

Visiting Sonnagh Fort

The ringfort is an open-air archaeological site that invites self-guided exploration. Visitors can walk the perimeter to examine the double bank and ditch system, step through the 4-metre wide south-eastern entrance, and observe how the landscape was engineered for defence. The nearby spring remains a visible feature, grounding the site in its practical medieval context. From the ridge, the view stretches across Lough Gowna’s drumlin-fringed waters and out toward the surrounding plains. The adjacent wetlands also draw a steady variety of birds, adding a quiet natural soundtrack to the historic setting.

Practical Information

• Access & Cost: Both the lake’s launch points and Sonnagh Fort are free to access. The fort is unguided and has no on-site facilities; visitors should use the parking, toilets and refreshment options in Ballinalee or Aughnacliffe.
• Management: Sonnagh Fort is a National Monument, unguided and with no facilities on site. Lake amenities are looked after by the local county councils.
• Opening Hours: Open year-round with unrestricted access. Launch sites remain available in all seasons, though boating conditions depend on weather and water levels.
• Visitor Tips: Bring appropriate fishing licences and tackle if angling, wear sturdy footwear for navigating the ringfort’s earthen banks, and pack a waterproof layer for unpredictable Irish weather. A picnic basket makes the most of the lakeside setting.
• Safety & Etiquette: Follow local fishing regulations, stay on established paths to protect the fragile earthworks, and respect the quiet character of the area. Dogs are welcome but should be kept under control near wildlife zones and archaeological features.

Nearby Attractions

A short drive away, Leebeen Park has more lakeside walking and the ancient dolmens of the Aughnacliffe area. Ballinalee has a heritage centre if you want the local history, and Longford Town, a bit further out, brings St Mel’s Cathedral and the county’s best choice of places to eat.

Come in spring or autumn for the pike; leave summer for the paddlers, when the water is at its calmest.