Bryanston Square is an 800-by-200-foot (244 by 61 m) garden square in Marylebone, London. Terraced buildings surround it — often merged, converted or sub-divided, some of which remain residential. The southern end has the William Pitt Byrne memorial fountain. Next to both ends are cycle parking spaces.
The most notable merged building is the Swiss Embassy at the north-east end. The square's narrow northern and southern ends are joined by broad approach streets of the same British Regency date. More recent style flanks the mid-west range of the square in the form of No.s 31, 32 and 33 which are three times an ordinary range of its widths, meaning the numbering scheme today skips ten following numbers, destroyed to make room for these, to culminate with No.s 44 to 50 and the highest-numbered buildings of Great Cumberland Place – its corner houses, No.s 63 and 68. That street, this square and Wyndham Place run broad and straight for 750 metres without building projections between an 1821-built church and Marble Arch, moved to its permanent site in 1851.
Traffic circulates clockwise around the square and numbering runs anti-clockwise.