Leck Beck is a watercourse in Lancashire with its source on Crag Hill in Cumbria between Leck Fell and Casterton Fell. For several kilometres near the start of its course, the water flows into the Ease Gill Cave System, part of The Three Counties System, the longest cave system in Britain (and 26th longest in the world) via 14 major sink holes, to resurge at a major spring at Leck Beck Head. The Beck flows through Leck, Cowan Bridge and Overtown before joining the River Lune near Nether Burrow.