Hinchingbrooke House in Huntingdon, Cambridgeshire, was built around an 11th-century nunnery. After the Reformation it passed into the hands of the Cromwell family, and subsequently, became the home of the Earls of Sandwich, including John Montagu, 4th Earl of Sandwich, reputedly the "inventor" of the modern sandwich.
On 8 March 1538, Richard Williams (alias Cromwell) had the grant of the nunnery of Hinchinbrooke, in Huntingdonshire, for the undervalued price of £19. 9s. 2d. while he was an official Visitor overseeing the dissolution of the monasteries. His son, Henry Williams (alias Cromwell)—a grandfather of Oliver Cromwell—built the house adjoining to the nunnery, and upon the bow windows he put the arms of his family, with those of several others to whom he was allied.
There was a serious fire in 1830 and the house was restored/rebuilt by Edward Blore; it was further restored in 1894 and again in the 1960s. During the most recent restoration the entrance to the chapter house was discovered, but otherwise little of the medieval fabric is visible.
In 1970, it became part of Hinchingbrooke School, housing the 6th form. Hinchingbrooke School was formerly Huntingdon Grammar School which, on the site of what is now the Cromwell Museum in Huntingdon, was attended by Oliver Cromwell and Samuel Pepys. The school now has around 1900 pupils.
More recently, while still being used as a school, Hinchingbrooke House is turned into a critically acclaimed scare attraction in the Halloween season called 'The Horror at Hinchingbrooke House'. It is also used as a conference centre, and is also for, dinner dances and as a wedding venue. It is a Grade I listed building and is open for tours on Sunday afternoons in the summer season.