River Erne, Belturbet, Co Cavan
River Erne, Belturbet, Co Cavan Courtesy Caroline Gallagher

Slate River

📍 County Kildare and County Offaly, Kildare

🏛️ Attraction

Last updated: 28 April 2026

Overview

The Slate River (Irish: An Tarae) is a modest yet charming tributary of the Figile River, flowing through the heart of County Kildare before crossing into County Offaly. Rising near Ballynafagh Lake in the village of Prosperous, the river runs southwest, threading its way past historic towns, lush forests and the iconic Grand Canal. Its waters are home to a variety of fish, and its banks provide a peaceful backdrop for walkers, cyclists and anglers.

History

The name “Slate River” derives from the slate quarries that once dotted the surrounding landscape, a reminder of the region’s industrial past. In Irish, the river is called An Tarae, meaning “mill race”, a nod to the historic Sally Corn Mill at Rathangan. Earlier maps record the waterway as the Clashaghbane River, reflecting the layered history of the area. The river shaped settlement patterns, providing water power for mills and a natural corridor that the Grand Canal later followed in the late 18th century. The canal’s extension brought new houses for engineers and contributed to the layout of Rathangan town, which today sits at the confluence of the Slate River and the Grand Canal.

What to See & Do

Walking and Cycling

River Barrow Blueway
Courtesy Luke Myers

The river’s gentle course makes it ideal for leisurely walks and bike rides. From Rathangan, the Barrow Way towpath runs just moments from the town centre, offering a scenic route toward Robertstown or Monasterevin. Shorter, self‑guided loops weave through the river’s floodplain, allowing visitors to explore the surrounding countryside at their own pace.

Historic Bridges and Footbridges

Quiet Man Bridge, Connemara, Co Galway
Quiet Man Bridge, Connemara, Co Galway Courtesy Daniela Ugga Campbell

Several bridges span the Slate River, each with its own story. The R415 crosses at Littletown, while the R401’s Rathangan Bridge provides a picturesque view of the waterway in the heart of town. Downstream of this bridge, a charming footbridge offers a quiet spot for a pause, and the R414 bridge at Rathangan Demesne adds another layer of historic infrastructure.

Nature and Wildlife

Anglers will find the Slate River well‑stocked with northern pike, European perch and brown trout. The river’s clear waters and varied habitats support a healthy fish population, making it a popular spot for both casual and serious fishing.

SpeciesTypical SizeBest Season
Northern Pike30‑70 cmSpring & Autumn
European Perch15‑30 cmSummer
Brown Trout20‑40 cmYear‑round

Fishing

The Slate River is renowned for both coarse and game fishing. Trout are taken from 1 March to 30 September using fly or spin methods; early season fly fishing is especially productive before water levels fall in summer. Coarse anglers target roach, bream, perch and hybrid species, with the river’s higher banks offering good standing spots.

A permit is required for most stretches. Anglers can obtain licences from the Irish Angling Association or contact the local representative Mr Larry Foy (553 Kilberry, Athy) for up‑to‑date fee information.

Events & Festivals

During the August Bank Holiday weekend, Rathangan hosts the Rathangan Lughnasa Festival. The event celebrates local arts, crafts, music and sport, and the Slate River provides a scenic backdrop for the festivities. Visitors can enjoy live performances, craft stalls and riverside picnics.

Nearby Attractions

  • Ballyteague Forest – A short walk from the river leads into this mixed‑wood forest, perfect for birdwatching and gentle hikes.
  • Lullymore Heritage and Discovery Park – Situated on the Bog of Allen, the park offers interactive exhibits about the region’s peatland heritage and a chance to explore the bog’s unique ecosystem.
  • Grand Canal – The Slate River passes under the Grand Canal via the historic Derrymullen aqueduct, a striking piece of 19th‑century engineering.
  • Rathangan Town – The river runs through the centre of Rathangan, a vibrant community with cafés, pubs and a lively market scene. Local landmarks such as Spencer’s Bridge (a favourite fishing spot) and the ruins of The Dean’s House add cultural depth to a riverside stroll.
  • Bog of Allen – The river’s upper reaches flow through this extensive peatland, offering opportunities for nature walks and educational trails.

Practical Information

The Slate River is freely accessible to the public; there is no admission fee. Parking is available in Rathangan’s town‑centre car parks (free, with a few short‑stay spaces). The river’s towpaths are reachable via the R403, R415, R401 and R414 roads.

Public transport: Rathangan is served by local bus routes linking the town to Kildare town and Dublin, making the river an easy day‑trip destination.

Fishing regulations: A permit is required for most stretches. Check the latest local regulations and obtain any required permits from the Irish Angling Association or contact Mr Larry Foy (see above). Water levels can be low in summer, affecting fishing conditions.

Accessibility: The footbridges and towpaths are suitable for walkers of all abilities; the surrounding forest trails provide gentle gradients.

Because the Slate River flows through both County Kildare and County Offaly, visitors can explore two counties in a single outing, enjoying the blend of agricultural landscapes, historic towns and natural reserves that define this part of Ireland. Whether you are seeking a quiet spot to cast a line, a scenic route for a family walk, or simply a place to sit and watch the water glide past, the Slate River offers a tranquil slice of Irish countryside waiting to be discovered.