The listed building has a slate roof and an eighteenth or early nineteenth-century facade with band courses and quoins.

[4] The pediment has a firemark, a plaque noting that the building owner had given financially to the town fire department.

In addition to classroom space, the new Grange includes a garden, kitchen, ICT suite, science laboratory, and art and music facilities.

[13][14] While students and staff had already started using the new school building on Hadnock Road in February 2009, it wasn't officially dedicated until 23 September 2009.

[2][3] On 13 and 14 December 2010, it was announced that permission for the conversion of The Grange from a prep school to a boarding house had been granted.

[16][17] The alteration of The Grange is a component of the first phase of The Heart Project, a substantial renovation of Monmouth School which has recently been undertaken.