Sashes Island is an island in the River Thames in England at Cookham Lock near Cookham, Berkshire. It is now open farmland, but has Roman and Anglo-Saxon connections.
The island is located between Hedsor Water and the present navigation channel leading to Cookham Lock. It can be reached from Cookham by footbridges across three channels of the River Thames via Formosa Island and Mill Island. Its name is derived from Sceaftesege or "Sceaf’s Isle".
Coordinates 51°33'47.711" N -0°41'56.459" E