At 893 m, Cross Fell is the highest point in the Pennine hills of Northern England. It is also the highest point in England apart from the main Lake District peaks. The summit is a stony plateau being part of a 20 km long ridge running North West to South East, which also incorporates Little Dun Fell (842 m) and Great Dun Fell (849 m). The three adjoining fells form an escarpment that rises steeply above the Eden Valley on its south western side and drops off more gently on its north eastern side towards the South Tyne and Tees Valleys.
Cross Fell summit is crowned by a cross-shaped dry-stone shelter, though this is not the reason for the naming of the hill. On a clear day there are excellent views from the summit across the Eden Valley to the mountains of the Lake District. On the northern side of Cross Fell there are also fine views across the Solway Firth to the Southern Uplands of Scotland.
The fell is prone to dense hill fog and fierce winds. A shrieking noise induced by the Helm Wind (see below) is a characteristic of the locality. It can be an inhospitable place for much of the year. In ancient times it was known as "Fiends Fell" and believed to be the haunt of evil spirits. It has been speculated that this last feature may be why the fell became known as Cross Fell ('cross' meaning 'angry'). Another theory is that at some time a cross was placed at the summit in order to ward off the spirits. But the origin of the name is not known for sure.
A conspicuous local feature is the golf ball shaped radar installation on the summit of Great Dun Fell. This was built in the 1960s and serves to support civil air traffic control over the North Atlantic.