The Blackwater or Munster Blackwater is a river which flows through counties Kerry, Cork and Waterford in Ireland. It rises in the Mullaghareirk Mountains in County Kerry and then flows in an easterly direction across County Cork through the towns of Mallow and Fermoy. It then enters County Waterford where it flows through Lismore, before abruptly turning south at Cappoquin and finally draining into the Celtic Sea at Youghal Harbour in Cork. In total, the Blackwater is 169 km (105 mi) long.

County Cork is the largest and the southernmost county of Ireland, named after the city of Cork, the state's second-largest city. It is in the province of Munster and the Southern Region. Its largest market towns are Mallow, Macroom, Midleton, and Skibbereen. As of 2022, the county had a population of 584,156, making it the third-most populous county in Ireland. Cork County Council is the local authority for the county, while Cork City Council governs the city of Cork and its environs. Notable Corkonians include Michael Collins, Jack Lynch, Roy Keane, Sonia O'Sullivan, Cillian Murphy and Graham Norton.