Stump Cross Caverns is a limestone cave system between Wharfedale and Nidderdale in North Yorkshire, England. The caverns at Stump Cross are located beneath Greenhow hill, 1275 metres above sea level. Their name was taken from Stump Cross, which in ancient times marked the limit of Knaresborough Forest. The area above the caves consists largely of moorland, the nearest towns being Pateley Bridge and Grassington. One mile of the caves have been open to the public for many years, although the entire system is much more extensive than the show caves, extending more than 4 miles (6 km). It has not yet been fully explored.
The caves are thought to have been formed around 500000 years ago, although the process by which they were created began during a much earlier period in which the region was covered by ocean. They were discovered in January 1860 by William and Mark Newbould, who were amongst a group of miners prospecting for lead veins in the Yorkshire Dales. Some sources have given the date of their discovery as 1858. By 1867 1100 yards of the caves had been explored.
In 1922 the caves were explored more thoroughly by Christoper Long, a student at Caius College, Cambridge. His discoveries included stalactites in a range of colours, suggesting that they were impregnated with iron and lead. Long claimed that he had also discovered an underground lake, but is said to have sealed its entrance when the caves' owners refused to allow him a share of the revenue generated by tourism to the site.
The caverns were sold to potholer Septimus Wray in 1926 for £400, remaining in his family until 2003. In 1963 Geoffrey Workman spent 105 days in the caves, a World record, as part of a study on the effects of isolation on the body. Stump Cross developed into a tourist destination in the decades that followed, gaining an information centre, gift shop and a two-bedroomed cottage for the owners.
The caves gained Site of Special Scientific Interest designation, and the Reindeer Cave was opened to the public in 2000, forty-five years after it was first discovered. In 2001 the caves were affected by the cleanup of nearby farms during the foot-and-mouth crisis. By 2003 over 60000 people visited the caves every year. In the same year they were put on the market by then-owner Gordon Hanley, a descendent of Wray, for £675,000.
Several fossils have been discovered in the Stump Cross system. The initial discoverers of the caves found four near-complete reindeer fossils and a smaller skeleton believed to be that of an unborn reindeer. These have since been privately restored. Christoper Long's 1922 exploration reveald more prehistoric reindeer bones, and also those of wolverines. The wolverine bones are now on display at the site's visitor centre. Bison remains have also been found.