The River Alde rises near Laxfield, Suffolk, and flows towards Aldeburgh before following the coast south to Orford, where it is known as the River Ore. King Henry II built a castle in Orford to guard the estuary. Construction began in 1165 and ended in 1173.

The estuary has moved steadily southwards over the centuries as the Orford Ness, the longest vegetated shingle spit in Europe, has grown in length. The river now emerges into the sea some five miles further south at Shingle Street, a small hamlet close to Bawdsey.