Clapper Bridges were built on Dartmoor from about 1400 to carry packhorse trade routes over rivers and streams. The bridges consist of one or more large slabs. When several slabs were required to cross a river then stone piers were built well clear of the water.
Crossing considered that the Postbridge Clapper Bridge "is the finest example of these interesting objects on the moor". It is 42 feet 8 inches long. The central clapper stone is 8.5 feet above the river bed.
Crossing reported that during the early nineteenth century the central clapper stone was pushed into the river in apparently a misguided attempt to prevent ducks moving down stream. The stone was re-instated in 1880 but is now 'upside down and inside out'.