The mountains of Whernside (736 m/2,415 ft), Ingleborough (723 m/2,372 ft) and Pen-y-ghent (694 m/2,277 ft) are collectively known as the Yorkshire Three Peaks and form part of the Pennine range, encircling the head of the valley of the River Ribble, in the Yorkshire Dales National Park in the North of England.
The three peaks are composed primarily of limestone and millstone grit in alternating strata which give Ingleborough and Pen-y-ghent a distinctive, stepped appearance. Ingleborough has impressive areas of limestone pavement, and is riddled with caves, such as the White Scar Caves, and potholes which attract cavers from all over the UK. It is home to England's tallest waterfall at Gaping Gill, where the Fell Beck falls 110 m (361 ft) vertically down a pothole, into Britain's second largest cavern. The beck re-emerges further down the mountain at Ingleborough Cave, where tourists can take a guided tour of a floodlit part of the cave system. Whernside, being much more rounded, is visually less imposing than its neighbours, but its summit happens to be the highest point in Yorkshire.
The area is rich in historical interest and the summit of Ingleborough has the remains of a huge Iron Age hill fort, while the Settle-Carlisle Railway runs between the mountains, crossing the Ribblehead Viaduct at the base of Whernside.
The Pennine Way visits Horton and traverses the summit of Pen-y-ghent whilst the Ribble Way follows the River Ribble from its source near the bottom of Whernside to its mouth near Preston.
In "The 3 Peaks Challenge" walkers and hikers aim to complete a gruelling 37.5 km (23.3 mi) to 42 km (26.1 mi), depending on route, circuit of all three peaks with nearly 1,600 m (5,249 ft) of climb and descent within 12 hours, starting and finishing at the same point, as detailed by Alfred Wainwright in his 1971 guide to Walks in Limestone Country. The route most walkers take varies from the fell race in that most traverse the 'nose' of Pen-y-ghent from Brackenbottom Moor and do not climb directly from the Pennine Way. In addition, Whernside is generally traversed along the right of way to the east following the railway line, all of which add's extra milage to the route. The traditional route starts in the village of Horton in Ribblesdale at the Pen-y-ghent Cafe which runs a 'logging' service where walkers can be timed in and out. Those successful become eligible for membership of the Cafe's 'Three Peaks of Yorkshire Club'. The challenge is also very popular with charity sponsored walks and Saturdays in early summer can see several hundred walkers making their way around the route.
The circuit is also the scene of a fell race held in late April and in 2008 this hosted the World Long Distance Mountain Challenge. The Three Peaks cycle-cross race takes a longer, 61 km (38 mi), route across the peaks.
