The river Stour has its source in Cambridgeshire, flows east to the North Sea and, for much of its length, forms the county border between Suffolk and Essex. The lower reaches have been immortalised by John Constable who used the river for many of his most celebrated paintings.
The Stour forms a small part of the southern boundary of the Park. However a mill stream, the ‘New Cut’, which diverts most of the water from the river as it flows through the Park, then joins the Stour 100 yards south of the sluice gates which lie just outside the Park. The New Cut as far as the sluice gates also form part of the southern boundary of the Park. The mill has long since ceased to exist.
The Chilton Stream, which flows along most of the eastern boundary of the Park joins the New Cut just before the sluice gates. Together with the moat and two large ponds these areas of water form a tranquil home for a wide variety of wildlife including swans and ducks.
Above the main doorway of the Swan Public House in Clare is possibly the oldest inn sign in England, thought to be originally the base of an oriel window taken from Clare Castle. The sign shows a chained swan that may have been associated with the nobility of the Castle or their royal relatives.