The Forest of Pendle is the name given to an area of hilly landscape to the east of Pendle Hill in eastern Lancashire, roughly defining the watershed between the River Ribble and its tributary the River Calder. The forest is not identical to the modern local government district of Pendle, which is larger. And in fact the modern version of the forest has come to contain areas to the north and east of Pendle Hill which are partly in the district of Ribble Valley.
The area is not literally a forest in the modern sense of being heavily wooded, and has not been so for many centuries. Historically a somewhat larger area than the modern forest was one of the several royal forests of the area, under the control of Clitheroe Castle, or Honour of Clitheroe. Over its history, the forest has gone from being a medieval royal forest, to being labelled as an Area of Outstanding Natural Beauty.
In 1086, at the time of the Domesday Book, Pendle forest was part of the extensive forests in Blackburnshire, in the eastern part of what would become Lancashire. The entire area between the rivers Ribble and Mersey had been granted by William the Conqueror to Roger the Poitevin, and he in turn had granted most of this area to the de Lacy family of Pontefract. It was they who apparently built Clitheroe Castle soon after. The Forest of Pendle was within their manor of Ightenhill.
Within the honour of Clitheroe, two sets of forests were administered separately, those of Bowland, and those of Blackburnshire. The Blackburnshire forest had four detached parts: Pendle, Trawden, Accrington and Rossendale.