Gaping Gill (also known as Gaping Ghyll) is one of the unmistakable landmarks on the mountain of Ingleborough in North Yorkshire, a 105 metre deep pothole with the stream Fell Beck flowing into it. After falling through one of the largest known underground chambers in Britain, the water disappears into the bouldery floor and eventually resurges adjacent to Ingleborough Cave.
The first recorded attempted descent was by J. Birkbeck in 1842 who reached a ledge approximately down the shaft which bears his name. The first complete descent was achieved by Édouard-Alfred Martel in 1895.
Due to the number of entrances which connect into the cave, many different routes through and around the system are possible. Other entrances include Disappointment Pot, Stream Passage Pot, Bar Pot, Hensler's Pot, Corky's Pot, and Flood Entrance Pot. In 1983 members of the Cave Diving Group made the underwater connection into Ingleborough Cave.
The Bradford Pothole Club around Whitsun May Bank Holiday and the Craven Pothole Club around August Bank Holiday each set up a winch above the shaft to provide a ride to the bottom and back out again for any member of the public who pays a fee.
The shaft was believed for a long time to be the largest in Britain, until the existence of Titan in Derbyshire was publicised in 2006 following its discovery in 1999. Gaping Gill still retains the records for the tallest unbroken waterfall in England and the largest underground chamber naturally open to the surface.