Dentdale is the dale of the River Dee, slicing through the Pennines in the north-west parts of the West Riding of Yorkshire, in an elegant S-shape, finally in a straight line from south-east to north-west until opening out to discharge the Dee into the River Rawthey at Sedbergh.
The head of the dale is at Denthead, which is the location of a railway viaduct on the Settle–Carlisle line. It is on the west side of the watershed of the Pennines, and so is one of the few of the Yorkshire Dales that drain westwards towards the Irish Sea, its waters flowing by way of the Dee, the Rawthey and then the Lune to Morecambe Bay.
The dale was also known to the Romans although there is no evidence of settlement during that period. Place-name evidence suggests Norse settlement by the tenth century.
The dale was one of the last of the Yorkshire Dales to be enclosed in 1859.
The typical occupations in the dale were farming and worsted related. Several mills used the fast flowing waters of the River Dee to supply power to the mills. At least one of these was converted to the Dent Marble industry by 1810.  Whilst fishing on the Dee at Dentdale in the 1840s, William Armstrong saw a waterwheel in action, supplying power to a marble quarry. It struck Armstrong that much of the available power was being wasted and it inspired him to design a successful hydraulic engine which began the accumulation of his wealth and industrial empire.
Dent village is the main shopping and social centre of the dale. There are two other major villages; Dent Head and Gawthrop. Additionally there are two hamlets at the top of the dale - Cowgill (where Dent Station is located) and Stone House. It has been noted that it is increasingly difficult for young people and family groups to stay in the dale as housing becomes more unaffordable.
There are over 200 listed buildings and structures in Dentdale which include the railway viaducts, bridges, barns, farmhouse, mileposts and even telephone boxes. Only one building is Grade I listed: the Church of St Andrew in Dent.
The famous Settle–Carlisle Line passes across the eastern edge of the dale being carried over the becks that feed the River Dee on Dent Head Viaduct and over Artengill Beck on Arten Gill Viaduct.
A single, unclassified road runs through the dale from the nearest main road at Sedbergh (the A683 and A684) to Newby Head Moss, east of the dale head, where it meets the B6255 Hawes to Ingleton road.
The Dent Fault cuts across the valley close to the village of Gawthrop, marking a geological boundary between the Carboniferous Limestone of Deepdale and the Craven Dales to the south and the older Silurian and Ordovician rocks of the Howgill Fells to the north.
The Upper Dentdale Cave System, which is two miles east of Dent, was recognized as a site of Special Scientific Interest in 1998. The cave system extends for a mile beneath the valley floor under the River Dee and is notable for providing a unique insight into how caves are formed in valley floors.
Dent Marble was quarried and polished in Dentdale between 1760 and 1909. Both the viaducts that carry the Settle-Carlisle line over the dale are constructed from Dent Marble. The opening of the railway afforded the opportunity to export the marble out of the dale for the first time. The stone is not actually marble, it is a highly polished form of Black Limestone.
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