The River Stour forms the boundary between the counties of Suffolk and Essex, eventually flowing in the Stour estuary near Maninningtree. In 1705, an act of parliament established its lower reaches as a commercial waterway or 'navigation', between the town of Sudbury (half way along its length) and Cattawade, near Manningtree.
Since the decline of commercial activity early in the last century, most of the lock structures have disappeared and the majority of the river has reverted to a more natural environment. It now has greater physical and ecological diversity, and generally shallower water which is best appreciated in craft with a smaller draft.
The River Stour Trust is a registered charity that was established in 1968 to promote the interests of users of the Stour Navigation. The Trust has undertaken many restoration projects and organises numerous river-based activities every year. It has its headquarters at The Granary, Sudbury and runs a visitor and education centre at Great Conrad. The Trust also owns and operates two electric-powered boats which are used for public boat trips.