The Abbey River (Irish: Abhainn na Mainistreach) is a distributary arm of the River Shannon that flows around the northeastern, eastern, and southern shores of King's Island, Limerick before rejoining the Shannon at Hellsgate Island.Hellsgate Island is only visible at low tide. It is bridged by the Abbey Bridge, Baals Bridge, the Canal Bridge, Matthew Bridge, O'Dwyer Bridge, and the Sylvester O'Halloran Footbridge.
King's Island's encirclement by the Shannon and Abbey rivers made it a very defensible location, leading to the founding of Limerick as a Viking settlement in the ninth century. The Abbey River has played a defensive role throughout the city's history, not least during the Cromwelliansiege of 1650-51, and the Williamitesiege of 1691.
^Seán Duffy, ed. (1 December 2004). Medieval Ireland: An Encyclopedia. CRC Press. p. 458. ISBN0203502671. Viking raiding parties used the Shannon from the 830s, attacking churches along its route and, by mid-century, had established a settlement at Limerick, building a fortress on Inis Sibtond. It was a very strategic site, protected from the west by the Shannon and elsewhere by the Abbey River.
^Burke, James (1 August 2001). "Siege Warfare in Seventeenth Century Ireland". In Lenihan, Pádraig. Conquest and resistance: war in seventeenth-century Ireland. Brill Academic Publishers. p. 286. ISBN978-9004117433. Clearly it was Ginkel’s intention to launch an amphibious assault over the Abbey and then cross the boggy ground to the breach…. Such an assault would present many dangers. The river was not fordable and a bridge would have to be constructed under fire.