River Alyn

The River Alyn rises in the Clwydian hills and winds through the Clwydian Range and Dee Valley Area of Outstanding Natural Beauty. Its limestone bed carves the Alyn Gorge between Loggerheads and Rhydymwyn. The river passes the town of Mold, Flintshire’s county town, before joining the Dee near Wrexham. Three caves lie along its gorge: Ogof Hesp Alyn, Ogof Hen Ffynhonnau and Ogof Nadolig. In summer the river’s flow drops, leaving parts of its bed dry and exposing potholes and underwater caves. Mining has shaped the river’s course. The Milwr mine drainage tunnel diverts twenty-three million gallons of water daily from the Alyn into the Dee estuary at Bagillt. This alters the river’s volume and affects its landscape. The Alyn’s limestone surface still bears the marks of these changes. The Loggerheads area shows where the river once cut deeper into the rock. Visitors walk the gorge paths and peer into the cave entrances. The dry river bed reveals potholes and sinkholes carved by water over centuries. Views open across the limestone hills and the wooded valley. The Alyn’s clear waters reappear in winter when rain swells the flow again. The river remains a quiet corner of north-east Wales, where geology and history meet.