Cilurnum or Cilurvum was a fort on Hadrian's Wall mentioned in the Notitia Dignitatum, now identified with the fort found at Chesters (also known as Walwick Chesters) near the village of Walwick in Northumberland. It was built in 123 AD, just after the wall's completion. Cilurnum is considered to be the best preserved Roman cavalry fort along Hadrian's Wall and there is a museum on the site. 

The bridge carried a military road behind the wall across the River North Tyne, and was defended by the adjacent cavalry fort. There were at least two bridges on this spot. The first, less massive than its successor, was probably contemporary with the construction of the Wall in AD 122-4. It crossed the river on a series of at least eight hexagonal stone piers about 4 m (13 ft) apart: the first of these (from the east) can be seen where it has been incorporated into the stonework of the later abutment.

The overall length of the bridge between abutments was 61m (200 ft). The width of these piers suggests that the bridge was intended to convey a structure 3 m (10 ft) wide - the width of the Broad Wall in this area - and that it therefore carried Hadrian's Wall across the river with a series of small stone arches. The masonry appears to have been plain but substantial, and the surviving hexagonal pier bears traces of dovetail cramps of iron set in lead which would have held the stones tightly together. It is a Scheduled Ancient Monument.

The second bridge was far more massive, with splayed wing walls both north and south of the bridge's actual line. This abutment, its massive rectangular stones lifted into place using the lewis holes which are a feature of their upper surface, were held together with long iron ties channelled into the masonry to reinforce the front face. The lewis-holes widen as they penetrate. The lewis consisted of a split wedge which, after being inserted in the hole, was widened out to lock into it by the insertion of a strip of metal between the two halves of the wedge. The hook of the crane was then passed through the head of the lewis and the stone was ready for lifting.

From this solid abutment there sprang an elegant bridge with four arches supported on three substantial river piers, 10.4 m (34 ft) apart. Its overall length was 57.6 m (189 ft) and was intended to take a road carriageway. Few voussoirs (wedge-shaped stones from arches) have been found, but there is sufficient other evidence in the form of cornice blocks, grooved to take vertical parapet slabs, and angled mouldings, to show that the bridge was of stone, although others state that the second bridge had a timber superstructure. This second bridge seems to date from the early third century. There is no evidence for any further repair or alteration to the bridge after that date. There is a male fertility symbol carved into the northern face of the eastern abutment.

The site is now in the care of English Heritage.