Gaping Gill on Ingleborough Hill is the deepest pothole in the Yorkshire Dales, England, and one of many entrances to the Gaping Gill cave system.

The 110m deep pothole descends in two stages. A 60m shaft descends from the surface to Birbeck's Ledge; shortly below, the shaft breaks into the roof of Britain's largest underground chamber. Under normal weather conditions, Fell Beck falls from the surface to the floor of the Main Chamber, making it Britain's highest waterfall. The water disappears into the bouldery floor and is seen only intermittently in the further reaches of the cave system; it resurges from Ingleborough Cave.

The first recorded descent was that of M.J. Birkbeck in 1842, who was lowered a short way down; in a second attempt in 1850 he reached "Birkbeck's ledge". The first complete descent, by rope ladder, was by the French caver E.A. Martel in 1895. Martel's first attempt on 30th July was unsuccessful because of high water conditions. On 1st August he reached the floor of the Main Chamber, in a climb taking 23 minutes. A strong hauling party assisted the climb back out.

Other entrances to the system, which now totals 11.6km in length, include Disappointment Pot, Stream Passage Pot, Bar Pot and Flood Entrance Pot. The underwater connection to Ingleborough Cave was first made by members of the Cave Diving Group in 1983.

The shaft may be descended by the general public on the Spring and August Bank Holidays, when a winch system is set up.

Sources

Brook, D. et al., Northern Caves 2 - the Three Peaks, Dalesman Press, ISBN 1-85568-033-5
Farr, M., The Darkness Beckons, 1991, Diadem Press, ISBN 0-906371-87-2
Mason, E.J., Caves and Caving in Britain, 1977, Robert Hale, ISBN 0-7091-6195-6