Ilkley Moor is the highest part of Rombalds Moor, the moorland between Ilkley and Keighley in West Yorkshire, England, United Kingdom. The peat bogs rise to 402 m (1,319 ft) above sea level. It is famous as the inspiration for the Yorkshire "county anthem" On Ilkla Moor Baht 'at.
Ilkley Quarry is the site of the famous "Cow and Calf", a large rock formation consisting of an outcrop and boulder, also known as Hangingstone Rocks. The rocks are made of millstone grit, a variety of sandstone, and are so named because one is large, with the smaller one siting close to it, like a cow and calf. Legend has it that there was once also a "bull", but that was quarried for stone during the spa town boom Ilkley was part of in the 19th century. However, none of the local historians has provided any evidence of the Bull's existence.
According to local legend, the Calf was split from the Cow when the giant Rombald was fleeing an enemy, and stamped on the rock as he leapt across the valley. The enemy, it is rumoured, was his angry wife. She dropped the stones held in her skirt to form the local rock formation The Skirtful of Stones.
The name of the giant Rombald is likely to be a retrovention, due to the name of the entire 'Rombalds Moor', which is most likely to derive its title from the de Rommilles, who held the honour of Skipton in the thirteenth century.
The Moor was the scene of an alleged alien abduction in December, 1987; there is a famous photograph purporting to show an alien on the moor.
July 2006 saw a major fire on the moor which left between a quarter and half of it destroyed.
Located on the Woodhouse Crag, on the Northern edge of Ilkley Moor there is a swastika-shaped pattern engraved in a stone, known as the Swastika Stone In the figure in the foreground of the picture is a 20th century replica; the original carving can be seen a little further away, at the centre-left of the picture.
The local millstone grit not only gives character to the town of Ilkley but gives the area its acid soils, heather moors, soft water and rocky scars, like the Cow and Calf rocks. If you could stand in the position of Ilkley Moor, in the Carboniferous period 325 million years ago, you would be in a swampy area at around sea level with meandering river channels coming from the North. The layers in the eroded bank faces of stream gullies in the area represent sea levels with various tides depositing different sorts of sediment. Over a long period of time the loose sediments were cemented and compacted into hard rock layers. Geological forces lifted and tilted the strata a little towards the south-east and produced many small fractures, or faults.
Since the end of the Carboniferous time there has been a tremendous amount of erosion and more than a thousand metres of the coal-bearing rocks have been completely removed from the area. More recently, during the last million years or so, Ice Age glaciers modified the shape of the Wharfe valley, deepening it, smoothing it and leaving behind glacial debris.