The River Ouse ( /ˈuːz/ OOZ) is a river in North Yorkshire, England. The river is formed from the River Ure at Cuddy Shaw Reach near Linton-on-Ouse, about 6 miles downstream of the confluence of the River Swale with the River Ure. It then flows through the city of York and the towns of Selby and Goole before joining with the River Trent at Trent Falls, near the village of Faxfleet, to form the Humber Estuary. The length of the Ouse is about 84 km (52 mi) and the combined Ure/Ouse river is about 208 km (129 mi) making it the sixth longest river in the UK.

The Ouse's system of tributaries (which includes the Derwent, Aire, Don, Wharfe, Rother, Nidd, Swale, Ure, and Foss) drains a large upland area of Northern England, including much of the Yorkshire Dales and North York Moors.

The Ouse valley is a wide, flat plain; heavy rainfall in the river's catchment area can bring severe flooding to nearby settlements. In recent years both York and Selby, and villages in between, have been very badly hit. The river has two weirs with locks, at Linton-on-Ouse and Naburn, so that boats of 45.7 m length and 4.6 m beam can reach York. The Ouse is tidal up to Naburn Locks.

Yorkshire (/ˈjɔːkʃə/) is a historic county of Northern England and the largest in the United Kingdom. Due to its great size in comparison to other English counties, functions have been increasingly undertaken over time by its subdivisions, which have also been subject to periodic reform. Throughout these changes, Yorkshire has continued to be recognised as a geographical territory and cultural region. The name is familiar and well understood across the United Kingdom and is in common use in the media and the military, and also features in the titles of current areas of civil administration, such as North Yorkshire, South Yorkshire, West Yorkshire and East Riding of Yorkshire. The county's name is commonly abbreviated as Yorks.

Within the borders of the historic county of Yorkshire are areas which are widely considered to be among the greenest in England, due to the vast stretches of unspoiled countryside in the Yorkshire Dales and North York Moors and to the open aspect of some of the major cities. Yorkshire has sometimes been nicknamed God's Own County. The emblem of Yorkshire is the white rose of the English royal House of York, and the most commonly used flag representative of Yorkshire is the White Rose on a dark blue background, which after years of use, was recognised by the Flag Institute on 29 July 2008.Yorkshire Day, held on 1 August, is a celebration of the general culture of Yorkshire, ranging from its history to its own dialect.

Ouse may refer to:

and in the United Kingdom to: