The Three Sisters (Ireland)

thumb|Map showing the Three Sisters [[river system]]

thumb|280px|[[River Barrow near Bagenalstown, County Carlow]]

The Three Sisters () 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 the Waterford Harbour Estuary, which is east of Waterford city. 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).

The combined catchment area of the Three Sisters is 9,207 km², made up of the Suir's (3,610 km²), the Barrow's (3,067 km²) and the Nore's (2,530 km²).

The combined long term average flow rate of the Three Sisters into Waterford Harbour is 157 m³/s, almost half of which is made up of the Suir's (76.9 m³/s), followed by the Nore's (42.9 m³/s) and the Barrow's (37.4 m³/s).