The Worth Valley is a geographic area in West Yorkshire, England, that extends eastwards from Crow Hill and Oxenhope Moor, providing drainage for the River Worth for nearly 10 miles (16 km) to the River Aire. It is a side valley to Airedale, with the River Worth being a major tributary of the River Aire. The Worth Valley was important for its contribution to the textiles industry of the West Riding of Yorkshire and was furnished with several reservoirs to allow mills to operate within the valley. Most of the reservoirs are still in use into the modern day.