The name Pennines is believed to come from the Celticpennioroches, meaning "hill", although the earliest written reference to the name dates only from the 18th century.
The landscape of the Pennines are mostly upland areas of high moorland.
The Pennines make up the main watershed in northern England, dividing the eastern and western parts of the country. The rivers Eden, Ribble, and Mersey flow west towards the Irish Sea. On the other side of the watershed, the rivers Tyne, Tees, Swale, Calder, Aire, Don, and Trent flow east to the North Sea.