The Swift Ditch is a backwater of the River Thames in England, which was formerly the primary navigation channel. With the main river, it creates the large island of Andersey Island near Abingdon, Oxfordshire.
As early as 955 to 963 AD, the monks of Abingdon Priory built a canal to the Abbey from the direction of Swift Ditch. There is also evidence that the current course of the river to the confluence had been built by 1060. However the Swift Ditch remained the faster route (hence the name), and a pound lock was built at its head by the Oxford-Burcot Commission in 1624. In 1788 several citizens of Abingdon wanted to divert navigation back to the current course and as a result Abingdon Lock was built near the town. Within ten years, the Wilts & Berks Canal connected to the current navigation channel at Abingdon.
The Swift Ditch is crossed by three bridges. The original Culham Bridge was built about the same time as the Abingdon Bridges across the site of a ford. It has been replaced by a more modern bridge carrying the A415 road beside it. A wooden footbridge further downstream carries the Thames Path.
Coordinates: 51°39′49″N 1°16′13″W / 51.66361°N 1.27028°W