Calderdale is a metropolitan borough of West Yorkshire, England, which had a population of 211,439. It takes its name from the River Calder, and dale, a word for valley. The name Calderdale usually refers to the borough through which the upper river flows, while the actual landform is known as the Calder Valley. Several small valleys contain tributaries of the River Calder. The main towns of the borough are Brighouse, Elland, Halifax, Hebden Bridge, Sowerby Bridge and Todmorden.

West Yorkshire is a metropolitan and ceremonial county in the Yorkshire and the Humber region of England. It borders North Yorkshire to the north and east, South Yorkshire and Derbyshire to the south, Greater Manchester to the south-west, and Lancashire to the west. The city of Leeds is the largest settlement.