A pre-preparatory department for children aged 4–7 was constructed starting for the 2013–14 academic year.

There are four day houses, named Caswall's, Lambourne, Penn's, and Swallow's after alumni.

It was formally founded in 1629 by Samuel Harsnett, Archbishop of York and Vice-Chancellor of Cambridge University, and began with 16 "poor, clever" scholars.

The English section for local children studying arithmetic, reading and writing was housed in a building behind the King's Head public house, which was mentioned in Charles Dickens' novel Barnaby Rudge: A Tale of the Riots of 'Eighty.

Following a trend set by many HMC schools (which were mainly all-boys), the Sixth Form section became coeducational and its first girls were admitted in the summer term of 1974.