The River Calder is in West Yorkshire, in Northern England.
The Calder rises on the eastern slopes of the Pennines and flows through green countryside, former woollen-mill villages, and large and small towns before joining the River Aire near Castleford.
The river’s valley is generally known as the Calder Valley. The name Calderdale usually refers to the large urban and rural borough (centred on Halifax) through which the upper river flows. The lower reaches flow through the boroughs of Kirklees (based on Huddersfield) and Wakefield. However, the river does not flow through the centres of Halifax and Huddersfield, which are on the Calder’s main tributaries, Hebble Brook and the River Colne respectively. The only large town centres through which the Calder flows are Brighouse, Mirfield, Dewsbury and the city of Wakefield.
The river itself is only navigable in short sections, but these sections are connected by artificial “cuts” (e.g. Horbury Cut) to form the Calder and Hebble Navigation, a popular leisure waterway which is part of the connected inland waterway network of England and Wales.