The Owendalulleegh is a river in Connaught, Ireland, that originates in the Slieve Aughty Mountains and flows westward until it reaches Lough Cutra, near Gort in County Galway. From Lough Cutra, the water continues as the Beagh River, winding through Gort and a series of underground channels before eventually reaching the sea at Kinvarra. The river is historically notable for its brown trout populations, though a series of landslides at Derrybrien in 2003 caused significant damage to the fishery, potentially killing up to 100,000 fish and affecting spawning habitat through water pollution and siltation in the years that followed. One of the river's most distinctive natural features is an unusual delta of old willow-dominated wet woodland, developed behind vegetated sandbars at the river's mouth on Lough Cutra — a striking and ecologically rich environment that sets this water apart from typical Irish rivers.