The mausoleum stands on a hill in the grounds of Castle Howard and is raised on a wide grassy terrace encircled with a stone wall. A massive double flight of steps leads up to the main chamber of the mausoleum which is encircled with a peristyle of Doric columns and crowned with a shallow dome. Inside it has a coffered ceiling and richly carved entablature supported by Corinthian columns. This circular funerary chamber rests on the great square plinth formed by the vaulted burial vault below. The latter contains sixty three catacombs.