The Yorkshire Dales are a series of hills and valleys in the central Pennine region of Great Britain.
The hills were formed over 250 million years ago although the valleys were created later by the action of glacier erosion.
Limestone, sandstone and gritstone form the main landscape with millstone grit capping the Three Peaks, the highest three mountains in the Yorkshire Dales.
The rivers Aire, Nidd, Swale, Ure and Wharfe in the Eastern Dales flow into the North Sea via the rivers Ouse and Humber. In the Western Dales the rivers Eden, Lune and Ribble flow into the Irish Sea.
Some 680sq miles (1760sq Km) of the Yorkshire Dales are within the National Park.
Nidderdale and a section of the Howgills, both areas of outstanding beauty, lie outside the Park boundary.