Input (grade 4): The river's source is at Irwell Springs on Deerplay Moor, approximately 1.5 m north of Bacup, in the parish of Cliviger, Lancashire.
Output (grade 3): The start of the river is at Irwell Springs on Deerplay Moor, about 1.5 m north of the town of Bacup, in the parish of Cliviger, Lancashire.