Hardcastle Crags is a wooded Pennine valley in West Yorkshire, England, owned by the National Trust. Historically part of the West Riding of Yorkshire, it lies approximately 2 miles (3.2 km) north of the town of Hebden Bridge.
Approximately half a mile along the valley there is a 19th-century cotton mill called Gibson Mill. The mill was water powered and has been renovated to demonstrate renewable energy sources and a sustainability strategy. It is surrounded by 400 acres (1.6 km2) of unspoilt woodland and crossed by 30 miles (48 km) of footpaths. The former cotton mill was one of the first powered mills built at the start of the Industrial Revolution.
Water powered turbines, photo voltaic panels, composting toilets, a wood burning boiler, a wood burning ceramic stove and locally sourced reclaimed interior materials have gone into making the venture sustainable.
The mill reopened on Saturday, 24 September 2005 and there are exhibits about the mill and its workers.