River Boyle

Boyle River
Boyle River at Knockvicar.
Native name	An Bhúill
Basin features
Main source	Lough Gara, County Mayo.
River mouth	Atlantic Ocean via the River Shannon

The Boyle River is a river in Ireland. It forms part of the Shannon River Basin. It flows from Lough Gara on the Sligo/Roscommon border and flows through the town of Boyle to Lough Key. From there is flows eastwards through the village of Knockvicar to the River Shannon at Lough Drumharlow, near Carrick-on-Shannon.

The length of the Boyle River (from its source in Mayo to the Shannon) is 64.4 km (40ml). The area of the Boyle river basin is 725 km²

The Upper Shannon catchment, above Carrick-on-Shannon (area: 1,301 km²) has two distinct reaches: The River Shannon (basin area: 576 km²) which rises in Cavan and the Boyle River (basin area: 725 km²), with its source in Mayo which have their confluence at Lough Eidin/Drumharlow approximately 4.7 km upstream of Carrick-On-Shannon.

The Boyle River has its origins in the rivers Lung and Breedoge which flow into Lough Gara. The 29 km (18 mi) Lung River is fed by Urlaur Lough and Errit Lough on the Mayo/Roscommon border.

The river flow from the furthest reaches of the Boyle catchment to Limerick city has a measurement of 290 km (180ml). When added to the Shannon's 102.1 km (63.5ml) estuary this gives a total river flow of 392.1 km (243.5ml), which makes it the longest river within the River Shannon basin (from source to mouth), 31.6 km (19.5ml) longer than the Shannon Pot source.