River Nore in the context of "Waterford Harbour"

Shown here are all the major rivers and tributaries of Ireland with their lengths (in kilometres and miles). Starting with the Northern Ireland rivers, and going in a clockwise direction, the rivers (and tributaries) are listed in regard to their entry into the different seas: the Irish Sea, the Celtic Sea and the Atlantic Ocean. Also shown are two tables. Table 1 shows the longest rivers in Ireland with their lengths (in kilometres and miles), the counties they flow through, and their catchment areas (in square kilometres). Table 2 shows the largest rivers in Ireland (by mean flow) in cubic metres per second.

The longest river in Ireland is the River Shannon, at 360.5 kilometres (224.0 mi). The river develops into three lakes along its course, Lough Allen, Lough Ree and Lough Derg. Of these, Lough Derg is the largest. The Shannon enters the Atlantic Ocean at the Shannon Estuary. Other major rivers include the River Liffey, River Lee, River Swilly, River Foyle, River Lagan, River Erne, River Blackwater, River Nore, River Suir, River Barrow (The Three Sisters), River Bann, River Slaney, River Boyne, River Moy and River Corrib.

The River Suir (/ʃʊər/ SHOOR; Irish: an tSiúr [ənʲ ˈtʲuːɾˠ] or Abhainn na Siúire [ˌəun̠ʲ n̪ˠə ˈʃuːɾʲə]) is a river in Ireland that flows into the Celtic Sea through Waterford after a distance of 185 kilometres (115 mi).The catchment area of the Suir is 3,610 km.Its long-term average flow rate is 76.9 cubic metres per second (m/s), about twice the flow of either the River Barrow (37.4 m/s) or the River Nore (42.9 m/s) before these join, but a little less than the Barrow's flow when it meets the Suir 20 km downstream (over 80 m/s).

Popular with anglers, it abounds in brown trout and salmon. Although the Suir holds the record for a salmon taken from an Irish river (weighing 57 lb/26 kg, taken on a fly in 1874), as has been the case in many other Atlantic rivers, salmon stocks have been in decline in recent years.

The Barrow (Irish: An Bhearú) is a river in Ireland. It is one of The Three Sisters, the other two being the River Suir and the River Nore. The Barrow is the longest of the three rivers and, at 192 km (120 mi), the second-longest river in Ireland, behind the River Shannon. The catchment area of the River Barrow is 3,067 km before the River Nore joins it a little over 20 km before its mouth. The river's long term average flow rate, again before it is joined by River Nore, is 37.4 cubic metres per second. At the merger with the River Nore, its catchment area is ca. 5,500 km and its discharge over 80 m/s.

The Three Sisters (Irish: An Triúr Deirfiúr) are three rivers in Ireland: the River Barrow, the River Nore and the River Suir. The Suir and Nore rise in the same mountainous area in County Tipperary, near the Devil's Bit, while the Barrow rises in the Slieve Bloom Mountains in County Laois. The Nore flows into the Barrow about 17 km before the Suir and Barrow join to form an estuary called Waterford Harbour east of the city of Waterford. The rivers fan out to drain a large portion of the southern part of the island, including Counties Tipperary, Carlow, Kilkenny, Wexford and Waterford, among others.

The lengths of the three rivers of the Three Sisters are the Barrow - 192 km (119 mi), the Suir - 185 km (115 mi) and the Nore - 140 km (87 mi).

Kilkenny (Irish: Cill Chainnigh [ˌciːl̠ʲ ˈxan̠ʲəj], meaning 'church of Cainnech') is a city in County Kilkenny, Ireland. It is located in the South-East Region and in the province of Leinster. It is built on both banks of the River Nore. The 2022 census gave the population of Kilkenny as 27,184, the thirteenth-largest urban centre in Ireland.

Kilkenny is a tourist destination, and its environs include historic buildings such as Kilkenny Castle, St Canice's Cathedral and round tower, Rothe House, Shee Alms House, Black Abbey, St. Mary's Cathedral, The Tholsel, St. Francis Abbey, Grace's Castle, and St. John's Priory. Kilkenny is also known for its craft and design workshops, the Watergate Theatre, public gardens and museums. Annual events include Kilkenny Arts Festival, the Cat Laughs comedy festival and music at the Kilkenny Roots Festival.