1790 - 1795
Single-arch humpbacked canal bridge, built 1792, carrying Ashtown Road over Royal Canal. Squared rubble limestone parapet walls with limestone string course, limestone coping and carved oval limestone plaques '1792 Longford Bridge and Lock' to east and west elevations. Elliptical arch with dressed limestone voussoirs and keystone. Associated 10th canal lock located to west.
The Royal Canal Company was established in 1789 to construct a canal to provide freight and passenger transport between Dublin and the River Shannon. Construction began with the laying of the first stone of the lock at Phibsborough (now the 5th lock) in 1790 and construction was completed to Ashtown by 1792. The bridge at Ashtown was named for Lord Longford, one of the original directors of the Royal Canal Company and its construction is commemorated in a carved stone plaque on each face. The bridge exhibits good quality stonework, a testament to the skill of the craftsmen involved. Together with the 10th canal lock, the pair makes an attractive ensemble, enriching the townscape character of the area.