The River Uck is a river in East Sussex, United Kingdom, which drains a catchment starting near Crowborough in the North, Hadlow Down to the East and Laughton, East Sussex to the South. It flows through the town of Uckfield and into the River Ouse about 5 miles (8.0 km) north of Lewes. The River Uck has a scenic walk alongside it. The river burst its banks in 2000, flooding much of Uckfield and the surrounding countryside.