River Shannon Facts

The River Shannon is the longest river in Ireland, and it has a total length of approximately 360 km (224 miles). It rises in the Cuilcagh Mountains in County Cavan and flows through several counties, including Longford, Westmeath, Offaly, Tipperary, Limerick, and Clare, before reaching the Atlantic Ocean at Loop Head, County Clare.

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River Shannon Facts for Kids

  • The River Shannon is the longest river in Ireland, stretching over 360 km.
  • It flows through many counties, including Cavan, Longford, Westmeath, and Clare.
  • The River Shannon is home to many species of fish and wildlife.
  • It has many lakes, including Lough Ree and Lough Derg.
  • The River Shannon is an important source of water for irrigation and power generation.
  • The river is used for many recreational activities, including boating, fishing, and swimming.

The Geography

The Shannon rises from the Shannon Pot in Derrylahan, County Cavan. Its catchment area of 12.8 km2 contains Garvah Lough and sources from Pollnaowen and other streams. The river then subsumes a number of tributaries, some on its 11-county journey, before reaching Limerick and the Shannon Estuary.

Meandering through Ireland’s counties, the river collects Boyle, Inny, Suck, Mulkear, and Brosna, among others, along its path. Its highest point rests at Tiltinbane on Cuilcagh Mountain’s western edge.

Shannon River’s length is hard to specify. Its traditional value is 390km (240 mi). But Irish sources provide 360.5km (224 mi), 258.1 fresh, and 102.1 tidal km (160.4/63.4, respectively). Some guides point to 344km (214 mi), yet most won’t give an exact number because of the estuary’s nature.

That distance is measured between Shannon Pot and a line connecting Kerry Head and Loop Head – farthest shore points – plus Ardnacrusha shipping contribution (7km/4.3mi detraction). The 280 km ends where Shannon Estuary joins Fergus Estuary near Shannon Airport. Pre-surveying instruments ages used longer vital lengths.

Longest in Ireland, the Shannon measures 360.5 km (224 miles). 12th-century maps suggested the river flows south from source to mouth. There are many tributaries throughout the Shannon basin with longer headwater sources: Owenmore River, 372 km (231 mi) in County Cavan, and Boyle River, 392.1 km (243.6 mi), sourced in Mayo.

Innovative wellsprings fuel this regionally renowned waterway, giving life to a diverse array of unique currents. Her waters nourish Irish culture and temperate climate, providing generations of locals boundless pride and admiration.

The River Shannon is revered for its length and flow. It stretches 360km, with a 45% river course, and the rest is composed of lakes. Its rapids pour out 7,350ft/s on average at Limerick – twice as much as Corrib’s 3,700ft/s – while reaching 11,000ft/s total, including contributions from tributaries Os Feale (1,220ft/s), Maigue (550ft/s), Fergus (910ft/s) and Deel (260ft/s).

At Lough Ree, Shannon’s force is already substantial at 98m3/s – more than any other Irish river aside from Corrib in Galway. Intellectual curiosity yields remarkable insight; Shannon’s strength is truly felt along its full course.

Rising from the mighty Shannon Estuary, the Callows serve as a Special Area of Conservation. The area stretches with its winding river up to fourteen settlements – Kilrush, Tarbert, Glin, Foynes, Askeaton, and so on – until concluding in Dowra.

The Shannon is teeming with history; each settlement reveals something new and special about the land and its people. From Limerick’s offerings to Ballina’s timeless beauty, this river circumnavigates many natural and man-made wonders. Some discoveries are never too old to marvel at.


The River Shannon has several major tributaries or smaller rivers that flow into it. Some of the main distributaries of the River Shannon are:

  1. River Brosna: This river originates in County Offaly and flows into the River Shannon near Banagher, County Offaly.
  2. River Inny: This river rises in County Longford and joins the River Shannon near Longford town.
  3. River Suck: This river rises in County Galway and flows into the River Shannon near Shannonbridge, County Offaly.
  4. River Mulkear: This river rises in the Slieve Bloom Mountains in County Laois and flows into the River Shannon near Annacotty, County Limerick.
  5. River Deel: This river rises in County Tipperary and flows into the River Shannon near Adare, County Limerick.


Traveling along the River Shannon is an experience that has been enhanced by various canals constructed to facilitate transportation and increase trade.

The Royal Canal was one of the earliest canals to be built in the late 1700s, connecting Dublin to the Shannon. Meanwhile, the Grand Canal followed in its footsteps, with construction beginning in the same period; this network featured side branches running through several of Ireland’s cities, including Limerick and Galway.

In recent years, the Shannon-Erne Waterway was developed in order to create a navigable route between the Shannon and Fermanagh’s River Erne that runs into Northern Ireland. The Athlone Canal provided access between Athlone and the river approximately a century earlier.

These canals are meaningful as they evolved commerce and improved transportation for Ireland, as well as providing stunning tourist attractions today and excellent opportunities for recreational activities such as boating or fishing.


The River Shannon, at 360.5 km (224.0 mi) long, rises only 76 m (249 ft) above sea level. Its navigability has made it a prime target for investment: the ESB operates a hydroelectric generation plant at Ardnacrusha, and over €2.5 billion was put into shipping in the Shannon Estuary during the 1980s.

The upgrades included an oil jetty at Shannon Airport and a tanker terminal at Foynes. Aughinish houses a large alumina extraction plant, too; ships take raw bauxite from West Africa to be refined here before being exported to Canada for further refining into aluminum. Moneypoint power station opened in 1985 with its 915 MW coal-fired electricity fed by 150,000-tonne bulk carriers.


The Shannon Estuary used to be a fishing hub for hundreds of men. Fishermen at Limerick’s Clancy’s Strand employed the Gandelow to catch salmon, while people from Abbey Fishermen used a boat called a Breacaun and a net to fish between Limerick City and Plassey until 1929.

However, the creation of a dam at Ardnacrusha in 1929 drastically reduced the number of salmon, forcing fishermen to rely on quotas.

This all meant that by the 1950s, commercial salmon fishing was all but over. Although commercial activity has almost ceased, recreational fishing is still popular around the Shannon Estuary – especially at Kilrush, where Currachs are utilized in herring fishing, and drift netting is still practiced.