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.

[1][2] Hellsgate Island is only visible at low tide.

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.

In the early 2000s, a number of historical artefacts were discovered when the river was drained.

These included Limerick Port seal, intact mortar bombs from the 1690s and a Viking Age bronze artefact, circa AD 1000.