Rugemont Castle is a medieval earthwork in the village of Segenhoe in Bedfordshire, east of Brogborough Park Farm.
Early records are limited, but Segenehoe manor formed part of the barony of Wahull in the 11th century. The de Wahulls had come to England with the Norman Conquest of 1066, and they appear to have constructed a castle in the village, with a ringwork design, approximately 75 m across. The first documentary reference to the castle is in 1276, by when the de Greys family had acquired the barony. The castle was adjacent to Brogborough Park, which was around 30 acres in size in 1326. In 1524, Sir Henry Grey passed the local manor, and probably the park, to the Crown.
Oliver Cromwell is said to have slept at Brogborough during the English Civil War and to have made use of the earthworks of Rugemont Castle to repulse an attack from Royalist troops. Much of the site was destroyed by the construction of a building known as the Round House in the 17th century. The castle earthworks have been extensively damaged by agriculture, but the remains are protected under UK law as a Scheduled Monument. The Round House was destroyed in a fire in 1993 and only ruins remain.