The south and west sides of Russell Square were developed between 1818 and 1825 by James Patching who had acquired the land as early as 1806. The design was by Amon Henry Wilds and, like Regency Square, the facing above balcony level was originally of yellow brick, most of which has now been rendered, the original balconies with cast iron balustrades are still present. The houses on the west and south side are mainly Listed grade II with a considerable amount of original detailing. Most of the buildings on the north side date from the 1840s, although some may originally have been contemporary with the south side. The east side, which was demolished in 1964 to make way for the development of Churchill Square and Chartwell Court, was also built in the 1840's.
There is a passageway linking to Regency Square which is seen in the film of Graham Greene's "Brighton Rock", as is a view of the south side of the square in the opening credits.
Few early illustrations of the square have been found. Delamotte's watercolour of 1853 (below) shows a rectangular enclosure with irregular shrub borders and a central lawn with three small beds. This layout was present on the 1875 Ordnance Survey plan, except that the central beds had been reduced to one.
The original railings around the enclosure were identical to those around the houses on the south side of the square. Unlike Regency Square lamp standards were placed on the surrounding pavements and not within the enclosure railings. The centre of the lawn became dominated by a single tree which is shown on the Ordnance Survey plan of 1911 and is remembered by local residents as the main feature of the square in the 1940s.
Like Regency Square, title to the enclosure passed to Brighton Corporation under the 1884 Act, but access was still restricted to residents up until the outbreak of World War II, when the railings were removed and an air raid shelter was dug at the eastern end. The elm in the south east corner of the enclosure and possibly the lime at the northern edge survive from the pre-war period.
There are now a number of family run hotels and guest houses in the square. Very few properties remain in single ownership as houses are converted into flats. In 1990 development of what was once the Dutton Forshaw motor workshop site started at the north-west corner of the square, between the backs of the properties on the northern side of Regency Square and Castle Street, the old garage having been demolished in 1984. This development resulted in the office building currently occupied by BUPA and the houses and flats now known as Russell Mews.
As with Clarence Square, work was completed in 2002 to re-landscape the square and enclose it with new cast iron railings. As can be seen it is now an oasis of green in the city centre.