What is "packhorse bridge"

n. A narrow bridge with low parapets so as not to interfere with the panniers of a packhorse

A packhorse bridge is a bridge intended to carry packhorses ( horses loaded with sidebags or panniers) across a river or stream. Typically a packhorse bridge consists of one or more narrow (one horse wide) masonry arches, and has low parapets so as not to interfere with the horse's panniers. Multi-arched examples sometimes have triangular cutwaters that are extended upwards to form pedestrian refuges.

Packhorse bridges were often built on the trade routes (often called packhorse routes) that formed major transport arteries across Europe and Great Britain until the coming of the turnpike roads and canals in the 18th century. Before the road-building efforts of Napoleon, all crossings of the Alps were on packhorse trails. Travellers' carriages were dismantled and transported over the mountain passes by ponies and mule trains.