Longdendale is a valley in the Peak District of England, north of Glossop and southwest of Holmfirth. The name means "long wooded valley" and the valley is mostly in the counties of Derbyshire and Greater Manchester.

Glossop is a market town in the borough of High Peak, Derbyshire, England, 15 miles (24 km) east of Manchester, 24 miles (39 km) north-west of Sheffield and 32 miles (51 km) north of Matlock. Near Derbyshire's borders with Cheshire, Greater Manchester, South Yorkshire and West Yorkshire, between 150 and 300 metres above sea level, it is bounded by the Peak District National Park to the south, east and north. In 2021, it had a population of 33,340.