The Shannon is the longest and most water-rich river in Ireland. Its catchment area covers around 15,700 square kilometers. Almost 250 kilometers of the river course are navigable.
Many different values have been given for the length of the Shannon. A traditional value is 390 km. An official Irish source gives a total length of 360.5 km. Most Irish guides now give 344 km. Some academic sources give 280 km, although most will refuse to give a number. The reason is that there is no particular end to a river that empties into an estuary. The 344 km length relates to the distance between Shannon Pot and a line between Kerry Head and Loop Head, the furthest reaches of the land. (It also assumes the current shipping route via Ardnacrusha, which takes 7 km off the distance.) The 280 km distance finishes where the Shannon estuary joins the estuary of the River Fergus, close to Shannon Airport. Longer distances emerged before the use of modern surveying instruments.
At a total length of 360.5 km, this means it is the longest river in Ireland. That the Shannon is the longest river in either Ireland or Great Britain was evidently known in the 12th century, although a map of the time showed this river as flowing out of the south of Ireland.
The River Shannon means ‘wise river’. It is named after Sionnan, the granddaughter of Manannán Mac Lir (Son of the Sea), a sea deity in Celtic mythology. Sionnan means ‘possessor of wisdom” and the Irish name for the River Shannon is Abhainn na Sionainne. Sionainn is a combination of the words ‘sion’ (wise) and ‘abhainn’ (river).
Sionnan is the Goddess of the River Shannon. Legend has it that Sionnan went to Connla’s Well – the Well of Wisdom in the Celtic Otherworld (the realm of the dead). As Sionnan lifted the cover off the well, it erupted and the water flowed down the mountain dividing the country in two. Her body was washed down the mountain and she transformed into the goddess of the River Shannon.
During the middle Ages, numerous castles were built on its banks because it formed the border between the provinces of Leinster and Connacht. From the mid-18th century until the arrival of the railroad in Ireland, the Shannon was the main traffic route in the region. Ireland, which became independent after the First World War, invested extensively in the expansion of the river as part of the Shannon Power Development Project, the realization of which was commemorated in the information panels along the river between 1924 and 1930. To date, the dams of the Shannon with its power plants are the largest electricity supplier in Ireland.
Today tourists take the opportunity to take a houseboat vacation on the Shannon. The boat area is connected to the lake area of Lough Erne (Northern Ireland) by the Shannon-Erne Waterway. Another connection is made possible by the Grand Canal with the capital Dublin and the River Barrow. The leisure captains have over 800 km of connected waterways.
The source of the River Shannon is the Shannon Pot in the Cuilcagh Mountains in County Cavan.
The River Shannon begins in County Cavan flowing down through the middle of the country, almost separating the west from the east. If you look at River Shannon map, you’ll see the river creates a border between the western province of Connacht and the southern and eastern provinces of Munster and Leinster.
From the Shannon pot, the source of the mighty Shannon River, many tributaries join the Shannon on its way down south to the Shannon Estuary. Its main tributaries are the rivers Inny, Suck, Brosna, Fergus and Maigue. Many other smaller tributaries join the Shannon along its journey and these, plus the lakes and the river itself make up the Shannon River Basin, the largest basin in Ireland.
There are some tributaries within the Shannon River Basin which have headwaters that are further in length (from source to mouth) than the Shannon Pot source’s length of 360.5 km, such as the Owenmore River, total length 372 km in County Cavan and the Boyle River, total length 392.1 km with its source in Mayo.
Some parts of the River Shannon are actually quite shallow with a depth of about 0.5 meters in places. It falls just 18 meters in the first 250 km of its course. It rises only 76 meters above sea level at its highest point meaning that it isn’t very deep at all and as a result, the river moves quite slowly.
Due to the River Shannon’s shallow depth, the river hasn’t seen any industrial shipping. This coupled with the fact that it flows through some sparsely populated areas means the river is, in many parts, rather clean and unpolluted.
There are three main lakes on the River Shannon. The uppermost lake is Lough Allen in County Leitrim, although some of the lake is located in County Roscommon. Lough Allen is the smallest of the three main lakes on the River Shannon.
The next biggest lake on the River Shannon is Lough Ree, which separates counties Longford and Westmeath in the east from County Roscommon in the west. The most southerly, and also the largest lake on the River Shannon is Lough Derg. The shores of Lough Derg touch counties Clare, Galway and Tipperary. There are other smaller lakes on the Shannon dotted along its course including Lough Bofin, Lough Boderg and Lough Forbes.
The River Shannon creates a variety of different habitats for wildlife and plants. As a result, many different animals live in and around the river. In the Shannon Estuary, you’ll see bottlenose dolphins and all along the river, you’ll be able to spot Kingfishers, Whooper Swans, Black-tailed Godwits, Mute Swans, widgeons, and Golden Plovers.
The River Shannon is home to plenty of fish too and there is an abundance of fishing hotspots and coarse angling areas. In the River Shannon, you’ll find brown Pike, Bream, Perch, Roach, Rudd and Tench.
The mouth of the Shannon River is in the Shannon Estuary in County Limerick. This is where the River Shannon ends and flows into the Atlantic Ocean.
