Culham Bridge is a medieval bridge crossing a present backwater of the River Thames in England at Culham, Oxfordshire, near the town of Abingdon. The bridge crosses Swift Ditch which was at one time the main navigation channel of the River Thames until Abingdon Lock was built in 1790. The bridge formerly carried the A415 road from Abingdon to Dorchester, Oxfordshire, but was superseded in 1928 by a modern road bridge.