The River Ouse is a river in North Yorkshire, England.
Hydrologically, the river is a continuation of the River Ure, and the combined length of the River Ure and River Ouse makes it, at 129 miles (208 km), the sixth-longest river of the United Kingdom and (including the Ure) the longest to flow entirely in one county.
The length of the Ouse alone is about 52 miles (84 km) but the total length of the river is disputed.
Main tributaries are the Derwent, Aire, Don, Wharfe, Rother, Nidd, Swale, Ure, and Foss.
