It forms part of a sequence of structures on the main route to the house at Castle Howard, and is north of the Carrmire Gate and south of The Obelisk.
[1] Vaughan Hart describes its crowning pyramid as "evok[ing] the idea of death at the very entrance to the estate".
There is machicolation over the arch with a keystone and an inscribed plaque, reading "Carolus Howard comes Carliolensis hoc condidit anno dni mdccxix".
In the ground floor are round-arched sash windows forming an arcade with an impost band and keystones.
At the rear is a balcony on a Tuscan column, an L-shaped flight of stairs and a machicolated square turret.