Horse Guards is a historic building in the City of Westminster, London, between Whitehall and Horse Guards Parade. It was built in the mid-18th century, replacing an earlier building, as a barracks and stables for the Household Cavalry. The current and previous buildings were, between the early 18th century and 1858, the main military headquarters for the British Empire. Horse Guards originally formed the entrance to the Palace of Whitehall and later St James's Palace; for that reason it is still ceremonially defended by the King's Life Guard.

Whitehall is a road and area in the City of Westminster, Central London, England. The road forms the first part of the A3212 road from Trafalgar Square to Chelsea. It is the main thoroughfare running south from Trafalgar Square towards Parliament Square. The street is recognised as the centre of the Government of the United Kingdom and is lined with numerous departments and ministries, including the Ministry of Defence, Horse Guards and the Cabinet Office. Consequently, the name "Whitehall" is used as a metonym for the British civil service and government, and as the geographic name for the surrounding area.