The Royal Terrace (now the Adelphi Terrace) was the most prominent street within the Adelphi complex, running along the southern border of the site overlooking the Thames. It comprised a block of eleven four-storey houses, sitting over double basements, embellished with stucco pilasters in the central and end bays. These were the grandest and most expensive houses at the Adelphi, with large top-lit staircases, a view over the river, dining rooms on the ground floor, and two large drawing rooms on the first floor. However, the Royal Terrace was not only the location of fine houses, as beneath the roadway were small dwellings, lit by Diocletian windows, which Adam called cottages. Lower still were the roadways and warehouses in the arches below.
In 1872 the façade of the houses on the Royal Terrace were rendered in cement, and their general appearance was further altered when the Victoria Embankment was built in 1864-70, and the metal were balconies removed in 1872. The central block of the Adelphi complex, including the houses of the Royal Terrace on its south side, was demolished in 1936.