The most architectural space of the State Apartments, this expressive, deeply modelled corridor was originally built c. 1758 to the designs of the Surveyor General, Thomas Eyre. Based on the early 18th century corridor of Edward Lovett Pearce in the former Parliament House on College Green, it features a marching procession of vaults and arches which were originally top-lit. Regrettably an office storey was built over the skylights following complete reconstruction of the corridor in the 1960s as the result of differential settlement with the reconstruction of the adjoining Drawing Room. The corridor features exact plaster casts of the original arch detailing, and the original doorcases and fireplaces salvaged prior to rebuilding.

Dublin Castle is currently maintained by the Office of Public Works, and houses, among other things, offices of the Revenue Commissionersin a 20th-century building at the end of the Castle Yard, some elements of the Office of Public Works itself in an old stables area, and some functions of the Garda Síochána.

The castle complex also hosts the Chester Beatty Library, in a purpose-constructed facility.