William awarded Roger de Poitou the lordship of Bures in late 1066, so it seems that the most likely date of the motte building is 1067 or 1068, when Roger moved in to consolidate his hold over his new lands. However, at least one local historian suggests that the Mount Bures castle motte was erected by the Sackville family during the turmoil of the Civil War between King Stephen and Queen Maud (early to mid 12th century).
The mound was almost certainly surmounted by a wooden palisade, no trace of which now remains. The base of the mound is about 200 feet across, and it rises to about 35 feet. According to an account in 1763 it was then 80 feet high, and much worn, so that the original height was estimated at 100 feet high.
At the base of the mound is a ditch, now dry, but records indicate that there was a moat here as late as the 18th century. The ditch is about 10 feet deep and 30-40 feet wide. A modern wooden stair now runs up the side of the motte to enable visitor access, and to protect the mound from the wear and tear of too many people climbing up the sides. There are excellent views out over the valley of the River Stour and north into Suffolk.
The motte was augmented by a bailey enclosure, which may have occupied the same space as the current churchyard.
The motte can be visited at any reasonable time, and there is a rather worn sign explaining the history of the site. The path to the motte is signed from the church parking area. And speaking of the church, don't visit the castle without taking a minute or two to explore the church; its a really interesting old building.