To the immediate west of Richmond House and adjoining Whitehall stood the "House of the Earls of Loudoun and Mar", built 1687-93 by John Drummond, 1st Earl of Melfort, Secretary of State of the Kingdom of Scotland 1684-9, for use by holders of that office and demolished after 1820 to make way for Richmond Terrace built in 1822 and surviving today. It was divided into two separate dwellings, the leases of which were held personally after 1707 by the descendants of Loudon and Mar. Richmond House built by the 2nd Duke and burned down in 1791, stood to its east, closer to the river. The Loudoun and Mar house was acquired between 1766-90 by the 3rd Duke of Richmond, after which it also appears to have become known as "Richmond House".
Destroyed by fire
Richmond House was destroyed by a fire in December 1791, and was not rebuilt by the 3rd Duke or his descendants. The library and art collection were rescued from the fire and were removed to Goodwood House, where the surviving two wings were built to re-house them. The fire started in the bedroom of Henrietta Anne le Clerc, called "a protegée of the Duchess" and "a long acknowledged daughter of His Grace", believed to have been the Duke's illegitimate daughter, to whom he referred in his will as "Miss Henrietta Anne le Clerc, who resides with me and though Christened by the name of Anne only is called Henrietta and whom I have from her childhood" and to whom he bequeathed an annual income of £2,000. The events are recorded as follows in the Annual Register of 1791:
Replaced by Richmond Terrace
The lease of the site passed to other ownership and in 1822 was built the surviving structure of eight large terraced houses known as "Richmond Terrace", occupying approximately the same footprint and orientation. These became fashionable private residences, until the 1920s when the leases expired and they returned to use as government offices until the redevelopment of 1982.
1980s redevelopment
In 1987 Richmond Terrace Mews, behind the building, was built over and joined to the rear of Richmond Terrace to form a modern government office block to house the headquarters of the Department for Health and Social Security, the main entrance to which was number 79 Whitehall . The ministerial team and key National Health Service officials were based there until November 2017. The new building was designed by Sir William Whitfield, and was completed in 1987.
Site for temporary Parliament
In January 2018, the House of Commons voted to move to Richmond House in 2025, for an estimated six years, to allow a full renovation of the Palace of Westminster, which accommodates the Houses of Commons and Lords. Plans revealed in October 2018 indicated that most of the 1980s structure would be demolished in preparation for this move, with only the facade retained in front of a new building designed by Allford Hall Monaghan Morris, containing a permanent chamber and offices.