1721 in architecture

The year 1721 in architecture involved some significant events.

Buildings and structures

Bocking Windmill, Essex, England.{{cite web|url=https://historicengland.org.uk/listing/the-list/list-entry/1122492|publisher=English Heritage|title=Windmill, Church Street (south east side), Braintree, Essex|access-date=2008-05-25}}
7 Burlington Gardens, later Queensberry House, London, Giacomo Leoni's first design for England
Fort King George, along the Altamaha River in the modern-day US state of Georgia{{cite book|last=Coleman|first=Kenneth|title=A History of Georgia|publisher=University of Georgia|year=1991}}
Ruthven Barracks in Scotland completed
Jackson Square (New Orleans), New France
Nazarbaug Palace, Gujarat, India
Ellingen Residence in Ellingen, Bavaria completed in its Baroque form
Písek Gate, Prague, Czech Republic
Saint Paul the First Hermit Cathedral completed as parish church of San Pablo, Laguna, Philippines

March 5 – John Adam, architect, brother of Robert Adam and James Adam (died 1792)
March 26 - Nicolas Le Camus de Mézières, French architect (Bourse de Commerce) and author (died 1793)
date unknown
Francesco Sabatini, Sicilian architect working in Spain (died 1797){{cite book|last1=Charles|first1=Victoria|last2=Carl|first2=Klaus|title=Rococo |date=2014|publisher=Parkstone International|page=183|isbn=978-1-78310-390-4|url=https://books.google.com/books?id=t8qjAwAAQBAJ&pg=PA183}}
Thomas Sandby, English draughtsman, watercolour artist, architect, and teacher (died 1798)

February 11 – Carlo Francesco Bizzaccheri, Italian architect (born 1656){{cite book|title=Carlo Francesco Bizzaccheri (1655-1721)|first1=Nina A.|last1=Mallory|first2=John L.|last2=Varriano|year=1974|publisher=Society of Architectural Historians}}
June 11 – Sir Anthony Deane, English naval architect, shipbuilder and politician (born 1633)